Lecture 11: Signaling Pathways Flashcards
TGF-Beta1
Signaling molecule belonging to Transforming Growth Factor-Beta superfamily; activation occurs when proregions are separated from bioactive dimer
Bone morphogenic proteins (BMPs)
Signaling molecule belonging to Transforming Growth Factor-Beta superfamily; often acts by inhibiting other processes of the embryo or being inhibited by other molecules
Fibroblast Growth Factor Family
Regulation by various molecules that complex with various parts of the signal transduction machinery
Hedgehog Family
Related to segment polarity molecule in Drosophila; include Desert, Indian, Sonic hedgehog
Wnt Family
Related to segment polarity molecule in Drosophila; interacts with components of extracellular matrix
Delta-Notch pathway
Represses gene expression; Delta binds to Notch and Notch intracellular domain cleaved - binds with Deltex, enters nucleus, binds to Supressor of Hairless, binds to Enhancer of Split
Lateral Inhibition
Dominant cell expresses Delta signalling molecules on cell membrane, binds to Notch on neighboring cells and represses gene expression in neighboring cells
Receptor Tyrosine Kinase pathway - FGF
FGF binds to RTK and activates G protein which leads to activation of many pathways and ERK resulting in activation of transcription factors
Receptor Tyrosine Kinase pathway - TGFB
TGFB binds to ser/thr kinase receptor II, II dimerizes with receptor I and activates R-Smad and Co-Smad which translocates into nucleus and binds to cofactors
Hedgehog pathway
Shh complexes with cholesterol and translocated to cell surface by Dispersed; Shh-cholesterol inhibits inhibitory action of Patched on Smoothened; Smoothened signals release of Gli which translocates to nucleus and influences gene expression
Wnt pathway
Wnt binds to Frizled, interacts with intracellular Disheveled; Disheveled prevents degradation of B-catenins by destruction complex; B-catenins translocate to nucleus and activate transcription factors
What is the role of Dicer in the MiRNA pathway?
Dicer cleaves miRNA into small single strand of miRNA
What is the role of AGO protein in MiRNA pathway?
AGO loads onto miRNA and cleaves target mRNA
Retinol pathway
Retinol binds to RBP, which binds to a membrane RBP and retinol is released into cytoplasm; retinol binds to CRBP1; retinoic acid bound to CRABP1 and translocated into nucleus; Retinoic acid binds to RXR-RAR, binds to RARE, activates transcription
