1zsg
From Proteopedia
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| Gene: | ARHGEF7, COOL1, KIAA0142, P85SPR, PAK3BP, PIXB (Homo sapiens) | ||||||
| Activity: | Non-specific serine/threonine protein kinase, with EC number 2.7.11.1 | ||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||
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. 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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