Books for lectures / !!! SignMolecDiffProlif Pictures

Signaling Moleculess

●Receptors

–Ion channel linked receptors

–Enzyme-linked receptors: single pass

●intrinsic enzyme activities

●coupled to intracellular enzymes

–G-protein coupled: 7-pass serpentine

–Cytoplasmic and nuclear receptors

●Cytoplasmic transducers

●Nuclear targets

Ion Channel Linked Receptorsrs

!Commonly called transmitter-gated ion channels or ionotropic receptors

!Involved in rapid synaptic signaling

!Classically defined by acetylcholine (AChh)) receptor at neuromuscular junction

!Nerve impulse depolarizes axon, signal travelsels toto nerve terminal leading to opening of voltage--gatedgated Ca2+ channels, Ca2+ flows in and ACh is releasedeased

!ACh binds receptors on muscle cells leadingg toto opening of cation channel and Na+ flows in

Receptors Associated with Enzyme ActivityActivity

●Y kinases: 9 different classes

–eg. PDGF, FGF, insulin, EGF

●Y phosphatases

–eg. CD45

●guanylate cyclases

–eg. natriuretic peptide receptors

●S/T kinases

–TGF-β , activin and BMP

●lack activity but coupled to Y-kinaseses

Receptors with Tyrosine Kinase Activitytivity

Coupling insulin binding to multiple signal pathways

Intracellular Transducerrss

●S/T kinases

–PKA, PKC, MAPK, ERK, Raf, etc.

●phospholipases

–PLCγ

●lipid kinases

–PI3K, PKB/AKT

Receptor Coupling

●thru SH2 domains, bind to Y-phos.

–PLCγ , PI3K, grb2, Shc

–phosphatases (PTP)

●thru SH3 domains

–grb2, Sos