PAK4 (non-phospho Antibody – Rabbit Polyclonal

PAK proteins, a family of serine/threonine p21-activating kinases, include PAK1, PAK2, PAK3 and PAK4. PAK proteins are critical effectors that link Rho GTPases to cytoskeleton reorganization and nuclear signaling. They serve as targets for the small GTP binding proteins Cdc42 and Rac and have been implicated in a wide range of biological activities. PAK4 interacts specifically with the GTP-bound form of Cdc42Hs and weakly activates the JNK family of MAP kinases. PAK4 is a mediator of filopodia formation and may play a role in the reorganization of the actin cytoskeleton. Multiple alternatively spliced transcript variants encoding distinct isoforms have been found for this gene. [provided by RefSeq]

Function: Activates the JNK pathway. Plays a role in the reorganization of the actin cytoskeleton and in the formation of filopodia. Phosphorylates and inactivates the protein phosphatase SSH1, leading to increased inhibitory phosphorylation of the actin binding/depolymerizing factor cofilin. Decreased cofilin activity may lead to stabilization of actin filaments. Phosphorylates ARHGEF2. Ref.8

Catalytic activity: ATP + a protein = ADP + a phosphoprotein.

Subunit structure: Interacts with FGFR2 and GRB2

By similarity. Interacts tightly with GTP-bound but not GDP-bound CDC42/p21 and weakly with RAC1. Interacts with its substrate ARHGEF2. Ref.9

Tissue specificity: Highest expression in prostate, testis and colon.

Post-translational modification: Autophosphorylated on serine residues when activated by CDC42/p21. Ref.10 Ref.11 Ref.12 Ref.13 Ref.14 Ref.15 Ref.17Phosphorylated on tyrosine residues upon stimulation of FGFR2

By similarity. Ref.10 Ref.11 Ref.12 Ref.13 Ref.14 Ref.15 Ref.17

Sequence similarities: Belongs to the protein kinase superfamily. STE Ser/Thr protein kinase family. STE20 subfamily.Contains 1 CRIB domain.Contains 1 protein kinase domain.

Sequence caution: The sequence BAA86456.1 differs from that shown. Reason: Erroneous initiation. The sequence BAC11166.1 differs from that shown. Reason: Erroneous initiation.