p21-activated kinase 4 (PAK4, serine/threonine protein kinase PAK 4, KIAA1142)

Function

• activates the JNK pathway
• role in reorganization of the actin cytoskeleton & in formation of filopodia
• phosphorylates & inactivates the protein phosphatase SSH1, leading to increased inhibitory phosphorylation of cofilin
• decreased cofilin activity may lead to stabilization of actin filaments
• interacts with FGFR2 & GRB2 (putative)
• interacts tightly with GTP-bound but not GDP-bound CDC42/p21 & weakly with RAC1
• autophosphorylated on Ser when activated by CDC42/p21
• phosphorylated on Tyr upon stimulation of FGFR2

Structure

• belongs to the protein kinase superfamily, STE Ser/Thr protein kinase family, STE20 subfamily
• contains 1 CRIB domain
• contains 1 protein kinase domain

Alternative splicing

named isoforms=4

Expression

highest expression in prostate, testis & colon

More general terms

• p21 (CDKN1A)-activated kinase (PAK)

Database

• Kegg: http://www.genome.jp/dbget-bin/www_bget?hsa:1029
• OMIM: https://mirror.omim.org/entry/605451
• UniProt: http://www.uniprot.org/uniprot/O96013.html
• Entrez gene: http://www.ncbi.nlm.nih.gov/sites/entrez?db=gene&cmd=Retrieve&dopt=Graphics&list_uids=10298