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p21 Cdc42(rho-G)/Rac-associated kinase, PAK1, p65PAK or alpha-PAK

Function: - activated kinase acts on a variety of targets - likely to be the GTPase effector that links the Rho-related GTPases to the JNK MAP kinase pathway - activated by CDC42 & RAC1 - involved in dissolution of stress fibers & reorganization of focal complexes - involved in regulation of microtubule biogenesis through phosphorylation of TBCB - involved in regulation of signaling pathways involving MAPK8 & RELA [1] - activity is inhibited in cells undergoing apoptosis, potentially due to binding of CDC2L1 & CDC2L2 - activated by binding small G proteins - binding of GTP-bound CDC42 or RAC1 to the autoregulatory region releases monomers from the autoinhibited dimer, enables phosphorylation of Thr-423 & allows the kinase domain to adopt an active structure - also activated by binding to GTP-bound CDC42, independent of phosphorylation state of Thr-423 - phosphorylation of Thr-84 by OXSR1 inhibits this activation (putative) - homodimer in its autoinhibited state - active as monomer - interacts tightly with GTP-bound but not GDP-bound CDC42/P21 & RAC1 - binds to the caspase-cleaved p110 isoform of CDC2L1 & CDC2L2, p110C, but not the full-length proteins - component of cytoplasmic complexes, which also contain PXN, ARHGEF6 & GIT1 - autophosphorylated when activated by CDC42/p21 & RAC1 - inhibited by PAK1IP1 ATP + a protein = ADP + a phosphoprotein Cofactor: Mg+2 Expression: abundant in brain

General

p21 (CDKN1A)-activated kinase (PAK)

Properties

SIZE: MW = 61 kD entity length = 545 aa STATE: active state MOTIF: CRIB domain {75-88} MOTIF: Thr phosphorylation site {T84} Linker {89-269} MOTIF: Ser phosphorylation site {S220} kinase domain SITE: 270-521 MOTIF: ATP-binding site NAME: ATP-binding site SITE: 276-284 ATP-binding site NAME: ATP-binding site SITE: 299-299 aspartate residue {D389}

Database Correlations

OMIM 602590 UniProt Q13153 PFAM correlations Entrez Gene 5058

References

  1. Manser E et al A non-receptor tyrosine kinase that inhibits GTPase activity of p21cdc42. Nature 363:364 1993 PMID: 8497321
  2. UniProt :accession Q13153