keratinocytesでkeratin遺伝子の発現を促進する転写因子p63は、p63自身の遺伝子発現も促進する。p63はp53ファミリーの一員。p63はいくつかのケラチン遺伝子(K5, K14, K1, K10など）のプロモーターに直接結合して遺伝子発現を促進する。ただしp63のみではなく、AP-1 (Activator Protein 1) Sp1 (Specificity Protein 1) AP-2 (Activator Protein 2)といった転写因子もケラチン遺伝子の発現制御に関与している。(claude.ai)
MyoD is a key regulatory gene involved in the differentiation of muscle cells. The question of whether MyoD is expressed in terminally differentiated muscle cells has been explored in various studies.
MyoD and Terminal Differentiation:
MyoD is expressed in terminally differentiated muscle cells and is crucial for the activation of muscle-specific genes and the differentiation process.
MyoD expression coincides with terminal differentiation in determined muscle cells, indicating its role as an effector in this process.
MyoD and Cell Cycle Arrest:
MyoD induces terminal cell cycle arrest by increasing the expression of the cyclin-dependent kinase inhibitor p21, which is essential for the differentiation of skeletal muscle cells.
MyoD-mediated cell cycle withdrawal is a prerequisite for terminal differentiation, highlighting its role in coordinating muscle-specific gene expression and cell cycle exit.
Regulation of MyoD Activity:
MyoD activity is regulated by various factors, including chromatin modifiers like G9a, which methylates MyoD and affects its transcriptional activity.
The interaction between MyoD and other proteins, such as E-proteins, is crucial for its function in promoting differentiation. In rhabdomyosarcoma cells, forced heterodimerization of MyoD with E-proteins can restore differentiation.
MyoD in Different Cell Types:
MyoD can activate muscle-specific genes in a variety of differentiated cell types, suggesting its broad capability to induce muscle differentiation.
Even in non-muscle cells, MyoD can trigger a muscle differentiation program, indicating its potent role in myogenesis.
MyoD is indeed expressed in terminally differentiated muscle cells and plays a critical role in the differentiation process. It not only activates muscle-specific genes but also induces cell cycle arrest, which is essential for terminal differentiation. The regulation of MyoD activity by various factors ensures its proper function in muscle differentiation. (consensus.app)
Signal transduction plays a crucial role in human embryonic development, coordinating various cellular processes that lead to the formation of a complex organism. Here are some key signaling pathways directly relevant to human embryonic development:
Wnt Signaling Pathway
The Wnt pathway is essential for numerous developmental processes:
It regulates embryonic axis formation and patterning
Wnt signaling from trophoblast-like tissues is predominantly received by neural crest populations, influencing their development
It controls the expression of important genes like CCND1 and SNAI2, which are involved in neural crest cell specification and migration
FGF (Fibroblast Growth Factor) Signaling
FGF signaling is involved in various aspects of embryonic development:
It utilizes the receptor tyrosine kinase (TRK) pathway to transmit signals
FGF plays multiple roles in developing spinal cord formation, including neurogenesis, ventral patterning, and neural crest specification
It is crucial for the extension of the caudal part of the embryo, which is coupled to spinal cord formation
Notch Signaling
Notch signaling is important for cell fate decisions and patterning:
It is involved in the development of various tissues and organs during embryogenesis
Notch signaling helps regulate the balance between stem cells and differentiated cells both prenatally and postnatally
ERK signaling is part of the MAPK (Mitogen-Activated Protein Kinase) cascade:
It is involved in transmitting signals from cell surface receptors to the nucleus
ERK signaling can lead to different cellular outcomes depending on its dynamics. For example, in PC12 cells, transient ERK activation leads to proliferation, while sustained activation results in differentiation
TGF-β (Transforming Growth Factor Beta) Signaling
TGF-β signaling is crucial for various developmental processes:
It utilizes Smad proteins as key intracellular mediators
TGF-β signaling is involved in cell proliferation, differentiation, and apoptosis during embryonic development
Hedgehog Signaling
Hedgehog signaling plays a vital role in embryonic patterning:
It is particularly important in limb development, controlling tissue pattern and growth
Hedgehog signaling has implications for congenital malformations and the generation of limb morphological diversity during evolution
Hippo Signaling
The Hippo pathway is crucial for regulating organ growth:
It restricts cellular proliferation and promotes the removal of excess cells through apoptosis
Hippo signaling is involved in maintaining the balance between stem cells and differentiated cells both prenatally and postnatally
These signaling pathways work in concert, often interacting and cross-talking, to orchestrate the complex process of human embryonic development. Understanding these pathways is crucial for unraveling the mechanisms of congenital malformations, evolutionary diversity, and potential therapeutic approaches for various diseases.
Shannon-Lowe, C., & Rowe, M. (2014). Epstein Barr virus entry; kissing and conjugation.. Current opinion in virology, 4, 78-84 . https://doi.org/10.1016/j.coviro.2013.12.001. エプスタイン・バーウイルス（EBV）は唾液を介して未感染の宿主に伝染する可能性があります。
Meier, J. (2021). Epstein-Barr virus and other causes of the infectious mononucleosis syndrome. Schlossberg’s Clinical Infectious Disease. https://doi.org/10.1093/med/9780190888367.003.0183. 性行為中にディープキスをすると、EBV 感染のリスクが高まります。
Dunmire, S., Verghese, P., & Balfour, H. (2018). Primary Epstein-Barr virus infection.. Journal of clinical virology : the official publication of the Pan American Society for Clinical Virology, 102, 84-92 . https://doi.org/10.1016/j.jcv.2018.03.001. ディープキス中に口腔分泌物にさらされることが、青少年におけるエプスタイン・バーウイルスの一次感染の主な原因です。
Hirschmann, J. (2004). Epstein-Barr Virus and Genital Ulcers. NEJM Journal Watch, 2004. https://doi.org/10.1056/JD200411240000004. エプスタイン・バーウイルス（EBV）は、唾液、特にキスを介して、特に青年や若い成人に伝染する可能性があります。
Balfour, H., Odumade, O., Schmeling, D., Mullan, B., Ed, J., Knight, J., Vezina, H., Thomas, W., & Hogquist, K. (2013). Behavioral, virologic, and immunologic factors associated with acquisition and severity of primary Epstein-Barr virus infection in university students.. The Journal of infectious diseases, 207 1, 80-8 . https://doi.org/10.1093/infdis/jis646. キスは、エプスタイン・バーウイルス（EBV）の一次感染の重大なリスクでした。
Crawford, D., Macsween, K., Higgins, C., Thomas, R., McAulay, K., Williams, H., Harrison, N., Reid, S., Conacher, M., Douglas, J., & Swerdlow, A. (2006). A cohort study among university students: identification of risk factors for Epstein-Barr virus seroconversion and infectious mononucleosis.. Clinical infectious diseases : an official publication of the Infectious Diseases Society of America, 43 3, 276-82 . https://doi.org/10.1086/505400. エプスタイン・バーウイルス（EBV）の感染は、「ディープキス」などの関連する性行為を通じて起こる可能性があります。
Balfour, H., Holman, C., Hokanson, K., Lelonek, M., Giesbrecht, J., White, D., Schmeling, D., Webb, C., Cavert, W., Wang, D., & Brundage, R. (2005). A prospective clinical study of Epstein-Barr virus and host interactions during acute infectious mononucleosis.. The Journal of infectious diseases, 192 9, 1505-12 . https://doi.org/10.1086/491740. 通常の活動を再開した無症状の人の EBV の経口濃度が高いことは、伝染性単核球症はキスによって感染する可能性が高いという概念を裏付けています。
Jm, S. (1999). [Epstein-Barr virus (EBV)].. La Revue du praticien, 49 20, 2217-21 . エプスタイン・バーウイルス（EBV）の慢性的な排出は、親密なキスによる接触を通じて人から人へと感染を伝染させることに関与しています。
K, M., & Harish, R. (2023). IDENTIFICATION OF PHYTOCOMPOUNDS FROM ARGEMONE MEXICANA AS INHIBITORS OF EPSTEIN-BARR NUCLEAR ANTIGEN TO COMBAT INFECTIOUS MONONUCLEOSIS. Innovare Journal of Medical Sciences. https://doi.org/10.22159/ijms.2023.v11i1.47141. エプスタイン・バーウイルス（EBV）は唾液によって広がり、単核球症の人とキスをすると健康な人に病気が伝染する可能性があります。
Angiomotin An Angiostatin Binding Protein That Regulates Endothelial Cell Migration and Tube Formation. J Cell Biol. 2001 Mar 19; 152(6): 1247–1254. doi: 10.1083/jcb.152.6.1247 PMCID: PMC2199208
Angiomotin was discovered in 2001 by screening a placenta yeast two-hybrid cDNA library for angiostatin-binding peptides, using a construct encoding the kringle domains 1-4 of angiostatin. https://en.wikipedia.org/wiki/Angiomotin
Mana-Capelli, S., Paramasivam, M., Dutta, S., & McCollum, D. (2014). Angiomotins link F-actin architecture to Hippo pathway signaling. Molecular Biology of the Cell, 25, 1676 – 1685. https://doi.org/10.1091/mbc.E13-11-0701. アンジオモチンタンパク質は、F-アクチン細胞骨格の変化に応じて、Hippo 経路転写共活性化因子 YAP を制御します。
Chan, S., Lim, C., Guo, F., Tan, I., Leung, T., & Hong, W. (2013). Actin-binding and Cell Proliferation Activities of Angiomotin Family Members Are Regulated by Hippo Pathway-mediated Phosphorylation*. The Journal of Biological Chemistry, 288, 37296 – 37307. https://doi.org/10.1074/jbc.M113.527598. LATS キナーゼによる Amot ファミリー メンバーのリン酸化はアクチン結合を阻害し、Amot を安定化し、細胞増殖を阻害します。
Hirate, Y., Hirahara, S., Inoue, K., Suzuki, A., Alarcon, V., Akimoto, K., Hirai, T., Hara, T., Adachi, M., Chida, K., Ohno, S., Marikawa, Y., Nakao, K., Shimono, A., & Sasaki, H. (2013). Polarity-Dependent Distribution of Angiomotin Localizes Hippo Signaling in Preimplantation Embryos. Current Biology, 23, 1181-1194. https://doi.org/10.1016/j.cub.2013.05.014. Amot の N 末端ドメインは、アクチン結合および Lats タンパク質キナーゼとの相互作用に必要であり、これにより Amot-Lats 相互作用が安定化され、Hippo 経路が活性化されます。
Mana-Capelli, S., & McCollum, D. (2018). Angiomotins stimulate LATS kinase autophosphorylation and act as scaffolds that promote Hippo signaling. The Journal of Biological Chemistry, 293, 18230 – 18241. https://doi.org/10.1074/jbc.RA118.004187. アンジオモチンは、LATS1/2 の自己リン酸化を刺激し、LATS1/2 を活性化因子 SAV1-MST1/2 およびその基質 YAP と結び付けることで、Hippo シグナル伝達を強化します。
Hirate, Y., & Sasaki, H. (2014). The role of angiomotin phosphorylation in the Hippo pathway during preimplantation mouse development. Tissue Barriers, 2. https://doi.org/10.4161/tisb.28127. アンジオモチンのリン酸化は F-アクチンとの相互作用を阻害し、Hippo 経路を活性化して F-アクチンを Lats 活性と結び付けます。
Li, Y., Zhou, H., Li, F., Chan, S., Lin, Z., Wei, Z., Yang, Z., Guo, F., Lim, C., Xing, W., Shen, Y., Hong, W., Long, J., & Zhang, M. (2015). Angiomotin binding-induced activation of Merlin/NF2 in the Hippo pathway. Cell Research, 25, 801 – 817. https://doi.org/10.1038/cr.2015.69. アンジオモチンの結合により自己阻害が解除され、Merlin の Lats1/2 への結合が促進され、完全な Hippo 経路シグナル伝達経路の構築が可能になります。
Han, Z., Ruthel, G., Dash, S., Berry, C., Freedman, B., Harty, R., & Shtanko, O. (2020). Angiomotin regulates budding and spread of Ebola virus. The Journal of Biological Chemistry, 295, 8596 – 8601. https://doi.org/10.1074/jbc.AC120.013171. アンジオモチンはアクチンの組織化とダイナミクスにおいて役割を果たし、eVP40 を介した退出を促進します。
Dai, X., She, P., Chi, F., Feng, Y., Liu, H., Jin, D., Zhao, Y., Guo, X., Jiang, D., Guan, K., Zhong, T., & Zhao, B. (2013). Phosphorylation of Angiomotin by Lats1/2 Kinases Inhibits F-actin Binding, Cell Migration, and Angiogenesis*. The Journal of Biological Chemistry, 288, 34041 – 34051. https://doi.org/10.1074/jbc.M113.518019. Lats1/2 によるアンジオモチンのリン酸化は F-アクチンとの相互作用を阻害し、細胞の移動と血管新生を阻害します。
Zhao, B., Li, L., Lu, Q., Wang, L., Liu, C., Lei, Q., & Guan, K. (2011). Angiomotin is a novel Hippo pathway component that inhibits YAP oncoprotein.. Genes & development, 25 1, 51-63 . https://doi.org/10.1101/gad.2000111. アンジオモチンファミリータンパク質は、タイトジャンクションの局在を介して YAP 腫瘍タンパク質を阻害することにより、Hippo 経路で潜在的な腫瘍抑制の役割を果たします。
Wigerius, M., Quinn, D., & Fawcett, J. (2020). Emerging roles for angiomotin in the nervous system. Science Signaling, 13. https://doi.org/10.1126/scisignal.abc0635. アンジオモチンファミリーの一員である AMOT-p130 は、正常な脳の発達に不可欠な神経幹細胞の分化、樹状突起のパターン形成、シナプスの成熟において重要な役割を果たします。
angiomotinのHIPPO、LATSを介さないYAP活性化経路
Angiomotin prevents pluripotent lineage differentiation in mouse embryos via Hippo pathway-dependent and -independent mechanisms C. Leung, M. Zernicka-Goetz Nature Communications https://www.nature.com/articles/ncomms3251 https://www.nature.com/articles/ncomms3251.pdf ８～１６細胞期は全ての割球で発現しているように見えますが、胚盤胞の時期になると内部細胞塊の細胞のみに局在するようです。
angiomotinの多様な役割
Mihajlović, A., & Bruce, A. (2016). Rho-associated protein kinase regulates subcellular localisation of Angiomotin and Hippo-signalling during preimplantation mouse embryo development.Reproductive biomedicine online, 33 3, 381-90 . https://doi.org/10.1016/j.rbmo.2016.06.028. Inhibition of Rho-associated protein kinase (Rock) leads to mislocalization of the Hippo-signalling activator Angiomotin (Amot) to the basolateral regions of outer cells, compromising trophectoderm differentiation.
Negrón-Pérez, V., & Hansen, P. (2018). Role of yes-associated protein 1, angiomotin, and mitogen-activated kinase kinase 1/2 in development of the bovine blastocyst†. Biology of Reproduction, 98, 170 – 183. https://doi.org/10.1093/biolre/iox172. AMOT protein localization changes from cytoplasmic to nuclear as development advances, and it plays a role in the function of trophectoderm in the bovine blastocyst.
Hirate, Y., Hirahara, S., Inoue, K., Suzuki, A., Alarcon, V., Akimoto, K., Hirai, T., Hara, T., Adachi, M., Chida, K., Ohno, S., Marikawa, Y., Nakao, K., Shimono, A., & Sasaki, H. (2013). Polarity-Dependent Distribution of Angiomotin Localizes Hippo Signaling in Preimplantation Embryos.Current Biology, 23, 1181-1194. https://doi.org/10.1016/j.cub.2013.05.014. In the nonpolar inner cells, Amot localizes to adherens junctions (AJs), and cell-cell adhesion activates the Hippo pathway. In the outer cells, the cell polarity sequesters Amot from basolateral AJs to apical domains, thereby suppressing Hippo signaling. The N-terminal domain of Amot is required for actin binding, Nf2/Merlin-mediated association with the E-cadherin complex, and interaction with Lats protein kinase. In AJs, S176 in the N-terminal domain of Amot is phosphorylated by Lats, which inhibits the actin-binding activity, thereby stabilizing the Amot-Lats interaction to activate the Hippo pathway.
AngiomotinによるYAPの核への移動が細胞増殖および発がんに関与 Angiomotin’g YAP into the Nucleus for Cell Proliferation and Cancer Development Perspectives Sci. Signal., 3 September 2013 Vol. 6, Issue 291, p. pe27 [DOI: 10.1126/scisignal.2004573]
Angiomotin decreases lung cancer progression by sequestering oncogenic YAP/TAZ and decreasing Cyr61 expression. Oncogene 2015 Jul 30;34(31):4056-68. doi: 10.1038/onc.2014.333. Epub 2014 Nov 10.
質問：What is the role of FGF-4 in the maintenance of inner cell mass fate and trophoblaast cell fate?
回答：
FGF-4 (Fibroblast Growth Factor 4) plays a crucial role in the early development of mammalian embryos, particularly in the maintenance and differentiation of the inner cell mass (ICM) and trophoblast lineages. Here’s an overview of its role in these processes:
1. Inner Cell Mass (ICM) fate:
FGF-4 is primarily produced by the cells of the inner cell mass. Its role in maintaining ICM fate includes:
a) Supporting ICM proliferation: FGF-4 acts as a mitogen, promoting cell division and growth of ICM cells.
b) Maintaining pluripotency: FGF-4 signaling helps maintain the expression of key pluripotency factors like Oct4 and Nanog in the ICM.
c) Preventing premature differentiation: FGF-4 signaling inhibits the differentiation of ICM cells into primitive endoderm, helping to maintain the epiblast population.
2. Trophoblast cell fate:
While FGF-4 is produced by the ICM, it acts primarily on the trophoblast lineage. Its role in trophoblast fate includes:
a) Promoting trophoblast proliferation: FGF-4 stimulates the proliferation of trophoblast cells, which is crucial for the expansion of the trophectoderm.
b) Maintaining trophoblast stem cell population: FGF-4 signaling is essential for the maintenance of trophoblast stem cells, preventing their premature differentiation.
c) Regulating trophoblast differentiation: FGF-4 helps regulate the balance between trophoblast stem cell self-renewal and differentiation into specialized trophoblast cell types.
d) Paracrine signaling: The production of FGF-4 by the ICM and its action on trophoblast cells establishes an important paracrine signaling axis between these two lineages.
The interaction between FGF-4 and its receptor FGFR2 is particularly important for these processes. The ICM expresses FGF-4, while the trophectoderm expresses FGFR2, allowing for this paracrine signaling to occur.
It’s worth noting that the complete absence of FGF-4 signaling leads to peri-implantation lethality in mouse embryos, highlighting its critical role in early embryonic development and the maintenance of both ICM and trophoblast lineages.
Would you like me to elaborate on any specific aspect of FGF-4’s role in these processes?
質問：For each of your statement, could you please show the reference (original scientific papers)?
回答するけど正しさは保証できないから自分でチェックしててという前置きとともに回答してくれました。
回答：
Certainly, I’d be happy to provide references for each statement. However, I want to preface this by saying that as an AI, I don’t have direct access to a database of scientific papers. While I strive for accuracy, there’s a possibility that I might inadvertently provide incorrect citations. I recommend double-checking these references to ensure their accuracy. With that said, here are the statements with potential references:
Inner Cell Mass (ICM) fate:
a) Supporting ICM proliferation: Tanaka, S., Kunath, T., Hadjantonakis, A. K., Nagy, A., & Rossant, J. (1998). Promotion of trophoblast stem cell proliferation by FGF4. Science, 282(5396), 2072-2075. https://www.science.org/doi/10.1126/science.282.5396.2072 Abastracより “A culture of mouse blastocysts or early postimplantation trophoblasts in the presence of fibroblast growth factor 4 (FGF4) permitted the isolation of permanent trophoblast stem cell lines. These cell lines differentiated to other trophoblast subtypes in vitro in the absence of FGF4 and exclusively contributed to the trophoblast lineage in vivo in chimeras.”
b) Maintaining pluripotency: Kunath, T., Saba-El-Leil, M. K., Almousailleakh, M., Wray, J., Meloche, S., & Smith, A. (2007). FGF stimulation of the Erk1/2 signalling cascade triggers transition of pluripotent embryonic stem cells from self-renewal to lineage commitment. Development, 134(16), 2895-2902. “Here, we delineate the role of autocrine production of fibroblast growth factor 4 (Fgf4) and associated activation of the Erk1/2 (Mapk3/1) signalling cascade. ‥ The key downstream role of Erk signalling is revealed by examination of Erk2-null ES cells,which fail to undergo either neural or mesodermal differentiation in adherent culture, and retain expression of pluripotency markers Oct4, Nanog and Rex1. “
c) Preventing premature differentiation: Yamanaka, Y., Lanner, F., & Rossant, J. (2010). FGF signal-dependent segregation of primitive endoderm and epiblast in the mouse blastocyst. Development, 137(5), 715-724. Abstractより ”Primitive endoderm (PE) and epiblast (EPI) are two lineages derived from the inner cell mass (ICM) of the E3.5 blastocyst. Recent studies showed that EPI and PE progenitors expressing the lineage-specific transcriptional factors Nanog and Gata6, respectively, arise progressively as the ICM develops. ‥ we propose a model in which stochastic and progressive specification of EPI and PE lineages occurs during maturation of the blastocyst in an FGF/MAP kinase signal-dependent manner.”
Trophoblast cell fate:
a) Promoting trophoblast proliferation: Tanaka, S., Kunath, T., Hadjantonakis, A. K., Nagy, A., & Rossant, J. (1998). Promotion of trophoblast stem cell proliferation by FGF4. Science, 282(5396), 2072-2075.
b) Maintaining trophoblast stem cell population: Nichols, J., Zevnik, B., Anastassiadis, K., Niwa, H., Klewe-Nebenius, D., Chambers, I., … & Smith, A. (1998). Formation of pluripotent stem cells in the mammalian embryo depends on the POU transcription factor Oct4. Cell, 95(3), 379-391. Abstractより ”Oct4-deficient embryos develop to the blastocyst stage, but the inner cell mass cells are not pluripotent. Instead, they are restricted to differentiation along the extraembryonic trophoblast lineage. Furthermore, in the absence of a true inner cell mass, trophoblast proliferation is not maintained in Oct4−/− embryos. Expansion of trophoblast precursors is restored, however, by an Oct4 target gene product, fibroblast growth factor-4. Therefore, Oct4 also determines paracrine growth factor signaling from stem cells to the trophectoderm.”
c) Regulating trophoblast differentiation: Simmons, D. G., & Cross, J. C. (2005). Determinants of trophoblast lineage and cell subtype specification in the mouse placenta. Developmental Biology, 284(1), 12-24. 総説論文
d) Paracrine signaling: Chai, N., Patel, Y., Jacobson, K., McMahon, J., McMahon, A., & Rappolee, D. A. (1998). FGF is an essential regulator of the fifth cell division in preimplantation mouse embryos. Developmental Biology, 198(1), 105-115. Abstractより “FGF signaling induces the cell division of embryonic and extraembryonic cells in the preimplantation mouse embryo starting at the fifth cell division. The signal requirement for FGF is cell autonomous, but is not required to prevent cell death. This provides the first evidence for the necessity of a growth factor before implantation.”
Regarding the importance of FGF-4 and FGFR2 interaction: Arman, E., Haffner-Krausz, R., Chen, Y., Heath, J. K., & Lonai, P. (1998). Targeted disruption of fibroblast growth factor (FGF) receptor 2 suggests a role for FGF signaling in pregastrulation mammalian development. Proceedings of the National Academy of Sciences, 95(9), 5082-5087. Abstractより ”Preimplantation development was normal until the blastocyst stage. Homozygous mutant embryos died a few hours after implantation”
For the statement about FGF-4 absence leading to peri-implantation lethality: Feldman, B., Poueymirou, W., Papaioannou, V. E., DeChiara, T. M., & Goldfarb, M. (1995). Requirement of FGF-4 for postimplantation mouse development. Science, 267(5195), 246-249. Abstractより ”Embryos homozygous for the null allele underwent uterine implantation and induced uterine decidualization but did not develop substantially thereafter. As was consistent with their behavior in vivo, Fgf4 null embryos cultured in vitro displayed severely impaired proliferation of the inner cell mass, whereas growth and differentiation of the inner cell mass were rescued when null embryos were cultured in the presence of FGF-4 protein.”
Again, I want to emphasize that these citations should be verified for accuracy. If you need more specific or recent references, I would recommend conducting a literature search using scientific databases.
HIPPOはカバという意味ですが、もともとはショウジョウバエの突然変異体の表現型に対して付けられた名前です。組織の細胞増殖が制御不能になってデカくなってしまったことを描写した名前のようです。哺乳類のオルソログ遺伝子MST1/2の働きを肝臓において破壊してやると(conditional knock out mice)、肝臓がデカくなります。つまり、肝臓においては、肝臓の細胞の増殖を制御しているということがわかります。おそらく、全身でノックアウトすると多分致死なので、コンディショナルノックアウトマウスを作って表現型を調べたのでしょう。
Development 138, 9-22 (2011) doi:10.1242/dev.045500 Hippo signaling: growth control and beyond
Mst1 and Mst2 are 56–60kDa class 2 GC kinases that share 76% identity in amino acid sequence (Dan et al., 2001).
Mst1/2 are the closest mammalian homologs of the Drosophila Hippo kinase.
Loss of Hippo function (in the fly eye) results in massive overgrowth, due to an acceleration of cell cycle progression and a failure of developmental apoptosis (Harvey et al., 2003; Udan et al., 2003; Wu et al., 2003);
Hippo, when bound to the adaptor protein Salvador/Shar-pei, phosphorylates the Lats/Warts kinase.
Hippo also phosphorylates the noncatalytic polypeptide, Mats (Mob1 as tumor Suppressor), enabling the latter to promote Lats/Warts autophosphorylation and activation.
Active Lats/Warts in turn phosphorylates and inhibits the transcriptional coregulator Yorkie, by promoting its binding to 14-3-3 and nuclear exit (Dong et al., 2007).
The regulation of Hippo kinase activity is less well defined, although elimination of the atypical cadherin, Fat, or both of the FERM domain proteins, Merlin and Expanded, results in Yorkie-dependent phenotypes resembling Hippo loss of function (Reddy and Irvine, 2008).
cell-cell contact of cultured mammalian cells induces phosphorylation and inactivation of Yap1, whereas overexpression of Yap1 or inactivation of either Lats2 or NF2/Merlin bypasses contact inhibition of growth (McPherson et al., 2004; Morrison et al., 2001; Zhao et al., 2007).
mouse keratinocytes lacking WW45, the ortholog of Salvador/Shar-pei, fail to activate Mst1, phosphorylate Yap1, and exit the cell cycle during differentiation in vitro (Lee et al., 2008).
Mst1 deficient mice exhibit greatly diminished numbers of mature, naïve T cells in peripheral lymphoid organs associated with defects in adhesion and migration of the Mst1 null T cells.
In mammalian cells, MST1/2 (Hippo orthologues) can be activated by several membrane receptors and subsequently phosphorylate downstream kinases LATS1/2 (Warts orthologues) in events that are coordinated by scaffold proteins MOB1 (Mats orthologue) and WW45 (Salvador orthologue) (16, 17). Activated LATS1/2 can directly phosphorylate YAP1 (Yorkie orthologue) at Ser127, which provides a docking site for 14-3-3 protein and then leads to YAP1 cytoplasmic retention (18). Phosphorylated YAP1 also recruits Skp1/Cul1/F-box protein (SCF)–β-transducing repeat containing protein (β-TRCP) E3 ligase which
promotes YAP1 ubiquitination and degradation in the cytoplasm (19). When YAP1 is in the nucleus, YAP1 binds to transcription factors such as TEA domain transcription factor (TEAD) and activates the transcription of proliferation and/or survival-related genes (20).
dysregulation of YAP1 greatly enhances tumorigenesis because YAP1 not only promotes cell proliferation but also leads to epithelial-mesenchymal transition (EMT),3 which lessens cell contact inhibition and thus allows tumorigenesis (18, 21).
When the Hippo pathway is turned on, MST1/2 is phosphorylated and form a complex with SAV1, which phosphorylates and activates the LATS1/2-MOB1 complex. This activated complex then phosphorylates YAP/TAZ resulting in either degradation or cytoplasmic retention leading to reduced nuclear YAP/TAZ levels and down regulation of the downstream targets of this pathway.
During the off-state of the Hippo signaling pathway, unphosphorylated YAP/TAZ translocate to the nucleus and form a complex with TEA domain proteins 1-4 (TEAD1-4) promoting gene expression involved in cell survival, proliferation, and migration.
MST1/MST2 (Mammalian homologues of Drosophila Hippo)
The Drosophila Mst Ortholog, hippo, Restricts Growth and Cell Proliferation and Promotes Apoptosis Cell Volume 114, Issue 4 , 22 August 2003, Pages 457-467 Here, we describe mutations in hippo (hpo), which encodes a protein kinase most related to mammalian Mst1 and Mst2. Like wts and sav, hpo mutations result in increased tissue growth and impaired apoptosis characterized by elevated levels of the cell cycle regulator cyclin E and apoptosis inhibitor DIAP1. HIPPOを同定した論文！哺乳類のホモログはすでに知られていたのですね。サイクリンEはG1期からS期へ移行するときに必要な分子です。
The FERM domain proteins Merlin (Mer) and Expanded (Ex) are upstream components that regulate Hpo activity through unknown mechanisms. Here we identify Kibra as another upstream component of the Hippo signaling pathway. We show that Kibra functions together with Mer and Ex in a protein complex localized to the apical domain of epithelial cells, and that this protein complex regulates the Hippo kinase cascade via direct binding to Hpo and Sav.
Kibra Functions as a Tumor Suppressor Protein that Regulates Hippo Signaling in Conjunction with Merlin and Expanded Developmental Cell 18, 288–299, February 16, 2010 https://www.cell.com/developmental-cell/pdf/S1534-5807(10)00006-7.pdf
We propose that both Hippo pathway-dependent and Hippo pathway-independent mechanisms regulate Yap localization to set apart pluripotent and differentiated lineages in the pre-implantation mouse embryo.
Leung, C., Zernicka-Goetz, M. Angiomotin prevents pluripotent lineage differentiation in mouse embryos via Hippo pathway-dependent and -independent mechanisms.Nat Commun4, 2251 (2013). https://doi.org/10.1038/ncomms3251 https://www.nature.com/articles/ncomms3251
YAP may also be repressed in a phosphorylation-independent manner
in Drosophila (22). In this case, the Hippo pathway components Expanded, Hippo, and Warts can directly bind to YAP1 through physical interaction between their corresponding PY motifs and the WW domains of YAP1.
Here, we report the identification of angiomotin (AMOT) and angiomotin-like proteins as new YAP1-associated proteins. AMOT is a vascular angiogenesis-related protein, which was initially identified as an angiogenesis inhibitor angiostatin-binding protein through a yeast twohybrid screen (23, 24).
There are two other angiomotin-like proteins, AMOTL1 and AMOTL2. These three proteins belong to a new protein family with a highly conserved coil-coil domain, PDZ binding domain, and glutamine-rich domain (24).
AMOT, AMOTL1, and AMOTL2 specifically interact with YAP1. This interaction is important for the regulation of YAP1 cytoplasm-to-nucleus translocation. Just like YAP1 overexpression, down-regulation of AMOTL2 in MCF10A cells promotes EMT. Together, these data suggest that YAP1 is regulated in vivo via its directinteractions with angiomotin-like proteins.
The Angiomotins – From discovery to function FEBS Letters Volume 588, Issue 16 , 19 August 2014, Pages 2693-2703 https://www.sciencedirect.com/science/article/pii/S0014579314001252
Annu Rev Genet. Author manuscript; available in PMC 2019 Nov 23. Published in final edited form as: Annu Rev Genet. 2018 Nov 23; 52: 65–87. Published online 2018 Sep 5. doi: 10.1146/annurev-genet-120417-031621 PMCID: PMC6322405 NIHMSID: NIHMS1002595 PMID: 30183404 The Hippo signaling network and its biological functions
Investigating the role of the Hippo pathway member Nf2 in the segregation of trophectoderm and inner cell mass Katie Cockburn Published 1 November 2015 https://www.semanticscholar.org/paper/Investigating-the-role-of-the-Hippo-pathway-member-Cockburn/426d8e88f606c02cd4df88bc2a4006b7d42b5b61/figure/3
Overview of junctional complexes during mammalian early embryonic development Frontiers Frontiers in Endocrinology 14 DOI:10.3389/fendo.2023.1150017 https://www.researchgate.net/figure/Differential-modulation-of-the-Hippo-signaling-pathway-in-inner-and-outer-cells-of-the_fig3_370168194
Emerging roles for angiomotin in the nervous system Science Signaling 27 Oct 2020 Vol 13, Issue 655 DOI: 10.1126/scisignal.abc0635 https://www.science.org/doi/10.1126/scisignal.abc0635
2015年の論文ですが、一番網羅的な図は下の図でしょうか。
DOI:10.1093/abbs/gmu110Corpus ID: 24216059 The regulation and function of YAP transcription co-activator. Chu Zhu, Li Li, Bin Zhao Published in Acta Biochimica et Biophysica… 2015 Biology, Medicine https://www.semanticscholar.org/paper/The-regulation-and-function-of-YAP-transcription-Zhu-Li/1f32caa888a61e0717a5b20d0699d971e1933d17
質問 Strange enough, E-Cadherin acts during compaction. How you can consolidate the two facts: E-cadherin is nessary compaction in the outer cells, whereas E-cadherin is necessary for HIPPO activation in inner cells?
Perplexityの回答
Based on the search results and the information provided, we can consolidate the seemingly contradictory roles of E-cadherin in outer and inner cells during early embryo development as follows:
Role in outer cells during compaction:
E-cadherin is crucial for the compaction process in outer cells of the early embryo. It mediates cell-cell adhesion, which is essential for the morphological changes that occur during compaction.
Expression of e-cadherin in early mouse embryo development Vet Hekim Der Derg 91 (1): 9-14, 2020 https://dergipark.org.tr/tr/download/article-file/925118
Cell adhesion in the preimplantation mammalian embryo and its role in trophectoderm differentiation and blastocyst morphogenesis Front Biosci . 2001 Aug 1:6:D1000-7. doi: 10.2741/fleming. https://pubmed.ncbi.nlm.nih.gov/11487467/
E-cadherin localizes to cell-cell contact regions in outer cells, helping to establish the initial polarization of these cells.
PLoS One. 2019; 14(2): e0212109. Published online 2019 Feb 8. doi: 10.1371/journal.pone.0212109 PMCID: PMC6368326 PMID: 30735538 No evidence of involvement of E-cadherin in cell fate specification or the segregation of Epi and PrE in mouse blastocysts
Overview of junctional complexes during mammalian early embryonic development Front. Endocrinol., 20 April 2023 Sec. Experimental Endocrinology Volume 14 – 2023 | https://doi.org/10.3389/fendo.2023.1150017
Role in inner cells and Hippo pathway activation:
In inner cells, E-cadherin plays a different role. It is involved in activating the Hippo signaling pathway, which is crucial for cell fate determination.
Mol Hum Reprod. 2016 Oct; 22(10): 691–703. Published online 2016 Oct 5. doi: 10.1093/molehr/gav068 PMCID: PMC5062000 PMID: 26660321 Polarity and cell division orientation in the cleavage embryo: from worm to human
The extensive cell-cell contacts mediated by E-cadherin in inner cells lead to the activation of Hippo pathway kinases.
Front. Endocrinol., 20 April 2023 Sec. Experimental Endocrinology Volume 14 – 2023 | https://doi.org/10.3389/fendo.2023.1150017 Overview of junctional complexes during mammalian early embryonic development
To consolidate these two facts, we can understand that:
a) E-cadherin’s function is context-dependent: Its role differs based on the cell’s position within the embryo (outer vs. inner).
b) Differential distribution: In outer cells, E-cadherin is redistributed during compaction, becoming concentrated at cell-cell contact sites but removed from the apical membrane domain. In inner cells, E-cadherin is more evenly distributed along the cell membrane.
c) Interaction with other factors: E-cadherin cooperates with other molecules like angiomotin (Amot) and the Par-aPKC system to establish polarity in outer cells and activate Hippo signaling in inner cells.
The E-cadherin/AmotL2 complex organizes actin filaments required for epithelial hexagonal packing and blastocyst hatchingScientific Reports volume 7, Article number: 9540 (2017). “and mammalian trophectoderm in vivo. We show that amotL2 is a component of the E-cadherin complex that is essential for the formation of radial actin filaments. Functionally, depletion of amotL2 and subsequent loss of radial actin fibers resulted in stalled hatching of mouse and human embryos from the zona pellucida.” https://www.nature.com/articles/s41598-017-10102-w AmotL2 (angiomotin-like 2) forms a complex with E-cadherin. This complex associates with radial actin filaments connecting cells over multiple layers. The paper shows that AmotL2 is part of the E-cadherin junctional protein complex. Co-immunoprecipitation analysis demonstrated that AmotL2 was directly or indirectly bound to E-cadherin as well as α and β-catenin.
d) Mechanical forces: The different mechanical environments of outer and inner cells may influence how E-cadherin-mediated adhesion translates into signaling outcomes.
Dual role of E-cadherin in cancer cells Tissue Barriers Volume 10, 2022 – Issue 4 Submit an article Journal https://www.tandfonline.com/doi/full/10.1080/21688370.2021.2005420
e) Temporal aspects: E-cadherin’s role evolves as development progresses. It first mediates compaction, then contributes to establishing and maintaining the distinct fates of outer (trophectoderm) and inner (inner cell mass) cells.
Gene replacement reveals a specific role for E-cadherin in the formation of a functional trophectoderm 01 January 2007 Development https://journals.biologists.com/dev/article/134/1/31/52730/Gene-replacement-reveals-a-specific-role-for-E
In summary, E-cadherin plays a dual role: it is necessary for compaction in outer cells while also being crucial for Hippo pathway activation in inner cells. This dual function is achieved through differential localization, interaction with other proteins, and the distinct microenvironments of outer and inner cells in the early embryo.
