Cell Signalling II

Question	Answer
2' Messengers + signal transduction	cAMP PKA cGMP PKG
Adenylyl Cyclase	2 transmem domains joined by a cat IC domain
Adenylyl cyclase pathway	Ligand binds to GPCR + Adenylyl cyclase ATP -> cAMP cAMP binds PKA PKA catalytic domains + other proteins
Signal termination	cAMP Phosphodiesterase degrades cAMP to 5-MP
Guanylyl Cyclase function	Converts GTP into diffusable cGMP
2 forms	Membrane bound - + by external L Soluble cytoplasmic form* - + by intrinsic mol. e.g. NO
How is cGMP degraded	Degraded by cGMP phosphodioesterase
PIP2 +Pi	PIP2 -> PIP3 via PL3K PIP3*->PDK1->PKB-> Cell proliferation
PIP3*->PIP2	Via PTEN - a tumour surpressor
Breakdown of PIP2 in LBL	PLC splits PIP2 DAG-> PKC InsP3-> Ca2+ release
How does Ca2+ act as a 2' messenger?	Δ in [Ca2+] in cytosol constitutes the signal
^ [Ca2+]?	Influx of EC Ca2+ Release from IC stores e.g. ER/SR/Mito
Decrease [Ca2+]?	Ca2+ pumps sequester it back into organelle (remember the conc. in cytosol constitutes the signal).
Structure and function of Calmodulin	1. 4 Ca2+ binding sites 2. + When [Ca2+]>500nM 3. Ca-Calmodulin can bind + modify activity of target e.g. Calmodulin-dependent protein kinases (CAM Kinases)
Roles of CAM Kinases (4)	Regulates fuel metabolism Muscle contraction Cell division Inflammatory response
Kd	[L] where 1/2 R is bound Measure of binding affinity
Kd formula	[R][L]/[RL]
Deriving Kd from binding assay	Total Binding (A) - Nonspecific Binding (B) = Specific Binding (C) 1/2 [R] bound = Kd

Resource summary

	Created by J yadonknow over 6 years ago