Phospholipase C Pathway Calcium signaling

phospholipase c cleaving pip2 ip3 , dag

specific signals can trigger sudden increase in cytoplasmic ca level 500–1,000 nm opening channels in endoplasmic reticulum or plasma membrane. common signaling pathway increases cytoplasmic calcium concentration phospholipase c pathway.

many cell surface receptors, including g protein-coupled receptors , receptor tyrosine kinases activate phospholipase c (plc) enzyme.
plc hydrolyses membrane phospholipid pip2 form ip3 , diacylglycerol (dag), 2 classical second messengers.
dag recruits protein kinase c (pkc), attaching plasma membrane
ip3 diffuses endoplasmic reticulum, , binds ip3 receptor,
the ip3 receptor serves ca channel, , releases ca endoplasmic reticulum.
the ca ions bind pkc, activating it.

depletion of calcium endoplasmic reticulum lead ca entry outside cell activation of store-operated channels (socs). inflowing calcium current results after stored calcium reserves have been released referred ca-release-activated ca current (icrac). mechanisms through icrac occurs still under investigation, although 2 candidate molecules, orai1 , stim1, have been linked several studies, , model of store-operated calcium influx, involving these molecules, has been proposed. recent studies have cited phospholipase a2 beta, nicotinic acid adenine dinucleotide phosphate (naadp), , protein stim 1 possible mediators of icrac.

movement of calcium ions extracellular compartment intracellular compartment alters membrane potential. seen in heart, during plateau phase of ventricular contraction. in example, calcium acts maintain depolarization of heart. calcium signaling through ion channels important in neuronal synaptic transmission.