1zsg
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(New page: 200px<br /> <applet load="1zsg" size="450" color="white" frame="true" align="right" spinBox="true" caption="1zsg" /> '''beta PIX-SH3 complexed with an atypical pep...)
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Revision as of 18:34, 12 November 2007
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beta PIX-SH3 complexed with an atypical peptide from alpha-PAK
Overview
The PAK Ser/Thr kinases are important downstream effectors of the Rho, family GTPases Cdc42 and Rac, partly mediating the role of these G, proteins in cell proliferation and cytoskeletal rearrangements. As well as, small G proteins, PAK interacts with the Cdc42/Rac exchange factor, beta-PIX via the PIX SH3 domain and a nontypical Pro-rich region in PAK., This interaction is thought to affect the localization of PAK, as well as, increased GTP/GDP exchange of Rac and Cdc42. We have determined the, structure of the PIX-SH3/PAK peptide complex and shown that it differs, from typical Src-like SH3/peptide complexes. The peptide makes contacts, through the Pro-rich sequence in a similar way to standard SH3/peptide, complexes, even though the Pro residue positions are not conserved. In, addition, there are interactions with a Pro and Lys in the PAK, which are, C-terminal to the conserved Arg found in all SH3-binding sequences. These, contact a fourth binding pocket on the SH3 domain. We have measured the, affinity of PIX-SH3 for the PAK peptide and found that it is of, intermediate affinity. When PAK is activated, Ser-199 in the PIX-binding, site is phosphorylated. This phosphorylation is sufficient to reduce the, affinity for PIX 6-fold.
About this Structure
1ZSG is a Protein complex structure of sequences from Homo sapiens. Active as Non-specific serine/threonine protein kinase, with EC number 2.7.11.1 Full crystallographic information is available from OCA.
Reference
Structural analysis of the SH3 domain of beta-PIX and its interaction with alpha-p21 activated kinase (PAK)., Mott HR, Nietlispach D, Evetts KA, Owen D, Biochemistry. 2005 Aug 23;44(33):10977-83. PMID:16101281
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