Btk-dependent regulation of phosphoinositide synthesis.

Content Provider	Semantic Scholar
Author	Carpenter, Christopher L.
Copyright Year	2004
Abstract	Activation of the BCR (B cell antigen receptor) stimulates the production of both PtdIns(3,4,5) P3 and Ins(1,4,5) P3. PtdIns(3,4,5) P3 and Ins(1,4,5) P3 are generated from a common substrate, PtdIns(4,5) P2. In some systems, continuous PtdIns(4,5) P2 synthesis is necessary for maximal Ins(1,4,5) P3 production, but whether this is true for the BCR, and whether PtdIns(4,5) P2 synthesis is regulated following BCR activation, are not known. We found that Btk (Bruton's tyrosine kinase), a member of the Tec family of cytoplasmic protein tyrosine kinases, is constitutively associated with PIP5Ks (phosphatidylinositol 4-phosphate 5-kinases), the enzymes that synthesize PtdIns(4,5) P2. Btk functions as a shuttle to bring PIP5K to the plasma membrane as a means of stimulating PtdIns(4,5) P2 synthesis. The Btk-PIP5K complex appears to localize to lipid rafts. This complex provides a novel shuttling mechanism that allows Btk to regulate the production of the substrate required by both its upstream activator phosphoinositide 3-kinase and its downstream target phospholipase Cgamma2.
Starting Page	1
Ending Page	12
Page Count	12
File Format	PDF HTM / HTML
Alternate Webpage(s)	http://www.biochemsoctrans.org/content/ppbiost/32/2/326.full.pdf
PubMed reference number	15046600v1
Volume Number	32
Part	2
Journal	Biochemical Society transactions
Language	English
Access Restriction	Open
Subject Keyword	Activation action Antigens B-Cell Receptor Complex B-Lymphocytes Cascade Device Component Phosphatidylinositol 4,5-Diphosphate Phosphatidylinositols Phospholipase Plasma membrane Protein Tyrosine Kinase Proximal Interphalangeal Joint 5 Receptors, Antigen Stimulation (motivation) Tissue membrane United States National Institutes of Health biological signaling kinase activity phosphatidylinositol 3,4,5-triphosphate
Content Type	Text
Resource Type	Article