Physiology 3140A Lecture Notes - Lecture 5: Sh3 Domain, Sh2 Domain, Ras Superfamily
24 Nov 2016
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Document Summary
Similar to gpcrs, enzyme-linked receptors are transmembrane proteins with extracellular ligand binding domains. Their carboxyl-terminal domains either have intrinsic enzymatic activity or are directly associated with cytosolic enzymes. Each subunit of an enzyme-linked receptor has one transmembrane spanning domain. Insulin receptor family: receptors are dimers (inactive: ligand binding causes a conformational change brings two internal kinase domains together. Rtks are activated by two types of ligands: Insulin, insulin-like growth factor (igf-1: dimeric ligand, monomeric ligands. G protein (ras) vs g protein ( ): heterotrimeric g proteins have and subunits existing separately that associate during ligand binding and then dissociate upon activation. Know 5 main classes & their general function i. e. ras cell proliferation, differentiation, etc: failure to inactivate typically leads to cancer. Map-kinases: 3 serine/threonine kinases: ras activates map-kinase- kinase-kinase (raf, raf phosphorylates map- kinase-kinase (mek, mek phosphorylates map- kinase (mapk: erk1/2, mapk translocates to nucleus and phosphorylates transcription factors. Grb2 has sh2 domain that binds to phosphorylated tyrosine receptor.
