細胞生物学の総説を読んでいると「カノニカル経路」という言葉をよく目にします。
Wntの細胞内情報伝達機構にはいくつかの種類があります。カノニカル経路といわれるのはβ-カテニン経路です。カノニカル canonical とは「正規の」の意味。どっちを正規と呼ぶかは主観の問題なので、研究の歴史において早くから明らかになった経路がカノニカルなのでしょう。
総説などで、カノニカル経路が何なのかの説明をみかけることはありません。どういう意味なのか、一応確認しておきます。ChatGPTが的確に説明してくれました。
In cell biology, the term “canonical pathway” refers to the standard, well-characterized, or classical version of a signal transduction pathway that is typically the most commonly studied and understood version. In the context of signal transduction, when we refer to the canonical Wnt pathway, for example, it typically means the Wnt/β-catenin signaling pathway, which is the main or classical route by which Wnt signaling regulates gene expression.
Key Features of a Canonical Pathway:
- Main or classical pathway: It is the primary signaling route through which a ligand (e.g., Wnt, Hedgehog, etc.) exerts its effects on the cell.
- Specific downstream components: In a canonical pathway, specific downstream molecules are activated in a well-established sequence (e.g., Wnt binds to its receptor, leading to the stabilization of β-catenin, which translocates to the nucleus to regulate gene expression).
- General or broad role: Canonical pathways often have broader and more general roles in regulating various cellular processes such as differentiation, proliferation, and development.
Examples:
- Canonical Wnt pathway: Refers to the Wnt/β-catenin pathway, where Wnt signaling stabilizes β-catenin to activate gene transcription.
- Canonical TGF-β pathway: Involves the activation of Smad2 and Smad3, which translocate to the nucleus and regulate gene expression.
In contrast, non-canonical pathways are alternative signaling routes that do not follow the classical mechanism and often involve different downstream components and processes, like the Wnt/PCP (planar cell polarity) pathway or Wnt/Ca2+ pathway.
Summary:
The term “canonical pathway” in signal transduction refers to the classical or standard version of a signaling pathway that involves well-defined molecules and mechanisms, widely studied and understood. (ChatGPTの解説）