Hedgehog signaling pathway
Hedgehog Signaling Pathway
The Hedgehog signaling pathway is a crucial intercellular communication system in biology that regulates cell division and differentiation, among other processes. Pronounced as /ˈhɛdʒˌhɒɡ/, the term's etymology is derived from the Hedgehog (Hh) family of proteins, named for their spiky appearance in fruit fly embryos.
Overview
The Hedgehog Signaling Pathway is a key regulator of animal development and is present in all bilaterians. It plays a vital role in the growth, patterning, and morphogenesis of many tissues and organs. Abnormalities in this pathway can lead to diseases such as cancer and birth defects.
Components
The pathway is composed of the Hedgehog (Hh) ligands, the twelve-transmembrane protein Patched (Ptc), the seven-transmembrane protein Smoothened (Smo), and the Gli family of transcription factors.
Function
In the absence of Hh ligand, Ptc inhibits Smo, preventing the activation of the downstream pathway. When Hh ligands bind to Ptc, this inhibition is relieved, allowing Smo to activate the Gli transcription factors, which then regulate the expression of target genes.
Clinical Significance
Alterations in the Hedgehog signaling pathway can lead to various diseases. Overactivation of this pathway has been implicated in several types of cancer, including basal cell carcinoma and medulloblastoma. Conversely, reduced activity can result in congenital disorders such as holoprosencephaly.
See Also
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