Membrane recruitment of DOCK180 by binding to Ptdlns(3,4,5)P-3

Citation
S. Kobayashi et al., Membrane recruitment of DOCK180 by binding to Ptdlns(3,4,5)P-3, BIOCHEM J, 354, 2001, pp. 73-78
Citations number
35
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Biochemistry & Biophysics
Journal title
BIOCHEMICAL JOURNAL
ISSN journal
0264-6021 → ACNP
Volume
354
Year of publication
2001
Part
1
Pages
73 - 78
Database
ISI
SICI code
0264-6021(20010215)354:<73:MRODBB>2.0.ZU;2-G
Abstract
DOCK180 was originally identified as one of two major proteins bound to the Crk oncogene product and became an archetype of the CDM family of proteins . including Ced-5 of Caenorhabditis elegans and Mbc of Drosophila melanogas ter. Further study has suggested that DOCK180 is involved in the activation of Rac by the CrkII-p130(Cas) complex. With the use of deletion mutants of DOCK180. we found that the C-terminal region containing a cluster of basic amino acids was required for binding to and activation of Rac. This region showed high amino-acid sequence similarity to the consensus sequence of th e phosphoinositide-binding site; this led us to examine whether this basic region binds to phosphoinositides. For this purpose we used PtdIns(3,4,5)P- 3-APB beads, as reported previously [Shirai, Tanaka, Terada, Sawada, Shirai , Hashimoto, Nagata, Iwamatsu, Okawa, Li et al. (1998) Biochim. Biophys. Ac ta 1402, 292-302]. By using various competitors, we demonstrated the specif ic binding of DOCK180 to PtdIns(3,3,5)P-3. The expression of active phospho inositide 3-kinase (PI-3K) did not enhance a DOCK180-induced increase in GT P-Rac; however, the expression of PI-3K translocated DOCK180 to the plasma membrane. Thus DOCK180 contained a phosphoinositide-binding domain, as did the other guanine nucleotide exchange factors with a Db1 homology domain, a nd was translocated to the plasma membrane on the activation of PI-3K.