BIOL 2021 Chapter Notes - Chapter 13.12: Phosphatidylinositol, Inositol, Phospholipid

• School: York University
• Department: Biology
• Course: BIOL 2021
• Professor: Patricia Lakin- Thomas

Document Summary

Me(cid:373)bra(cid:374)e do(cid:373)ai(cid:374)s: inositol phospholipids have regulatory function. Inositol phospholipids undergo phosphorylation & dephosphorylation at 3", 4" & 5, positions of inositol sugar head groups to produce phosphoinositide"s (phosphatidylinositol phosphates, Figure 13-10 phosphatidylinositol (pi) & phosphoinositide (pips) (a,b) structure of pi, with free hydroxyl groups in inositol sugar. (c) phosphorylation of 1,2, or 3 hydroxyl groups on pi by pi & pip kinases produces different pip species. Named based on ring positions on inositol (in parentheses) & number of phosphate groups (subscript) to pi. Example c. kinases add phosphate groups (red arrow); phosphatases remove phosphate (green arrow). (e,d) phosphoinositide head groups are recognized by protein domains that differentiate b/t different forms. Different pips located in different membranes & membrane domains, where they associate with specific vesicle transport events. The secretory vesicles contain pi(4)p. when vesicles fuse with membrane, a pi 5-kinase converts pi(4)p into pi(4,5)p2. Pi(4,5)p2 helps recruit adaptor proteins to initiate formation of clathrin-coat pit.