This preview shows page 1. Sign up to view the full content.
Unformatted text preview: n previous slide. in this case the enzyme activated is not
adenyl cyclase but actually phospholipase C, a membrane-bound enzyme. this second messengers are metabolize-membrane lipids. phospho C catalyze conversion of structural lipid pho inositol to lipid
subunits, one which is soluble, the other is nonsoluble. the soluble lipid subunits is IP3 (diffuse to cytoplasm). the DAG is nonsoluble, remain in membrane. IP3's main function in cells is to release calcium
from internal stores. the purple thing is smooth ER. there are calcium ATPases in the ER that pump calcium into the lumen of ER. the ER/SR in muscle cell sequester (hides calcium) by store it into lumen of
ER-this help maintain low ca in cytoplasm (enabling local small increase of calcium to serve as second messenger) and also provide a store for the selective release of calcium in times needed. calcium is
release from store in the lumen of the ER by IP3 binding to a calcium ion channel in the ER membrane. calcium channel open, calcium diffuse out. calcium cause ce...
View Full Document
This document was uploaded on 03/09/2014 for the course EXSC 301 at USC.
- Spring '09