PAK2
Description
The PAK2 (p21 (RAC1) activated kinase 2) is a protein-coding gene located on chromosome 3.
Serine/threonine-protein kinase PAK 2 is an enzyme that in humans is encoded by the PAK2 gene. PAK2 is one of three members of Group I PAK family of serine/threonine kinases. The PAKs are evolutionary conserved. PAK2 and its cleaved fragment localize in both the cytoplasmic or nuclear compartments. PAK2 signaling modulates apoptosis, endothelial lumen formation, viral pathogenesis, and cancer including, breast, hepatocarcinoma, gastric and cancer, at-large, and, based on its kinase activity alone, peripheral nerve myelination during embryonic development.
== Discovery == The human PAK2 was identified as a downstream effector of Rac or Cdc42.
== Gene and spliced variants == The PAK2 gene is about 92.7-kb long. The gene contains 15 exons and generates three alternatively spliced transcripts - two of which code proteins of 524 amino acids and 221 amino acids, while the third one is a 371-bp non-coding RNA transcript(Gene from review) There are two transcripts generated from the murine PAK2 gene, a 5.7-kb transcript coding a 524 amino acids long polypeptide and a 1.2-kb long non-coding RNA transcript.
== Protein domains == Similar to PAK1, PAK2 contains a p21-binding domain (PBD) and an auto-inhibitory domain (AID) and exists in an inactive conformation. The p21 activated kinases (PAK) are critical effectors that link Rho GTPases to cytoskeleton reorganization and nuclear signaling.
Serine/threonine protein kinase that plays a role in a variety of different signaling pathways including cytoskeleton regulation, cell motility, cell cycle progression, apoptosis or proliferation (PubMed:7744004, PubMed:19273597, PubMed:19923322, PubMed:9171063, PubMed:12853446, PubMed:16617111, PubMed:33693784). Acts as a downstream effector of the small GTPases CDC42 and RAC1 (PubMed:7744004). Activation by the binding of active CDC42 and RAC1 results in a conformational change and a subsequent autophosphorylation on several serine and/or threonine residues (PubMed:7744004). Full-length PAK2 stimulates cell survival and cell growth (PubMed:7744004). Phosphorylates MAPK4 and MAPK6 and activates the downstream target MAPKAPK5, a regulator of F-actin polymerization and cell migration (PubMed:21317288). Phosphorylates JUN and plays an important role in EGF-induced cell proliferation (PubMed:21177766). Phosphorylates many other substrates including histone H4 to promote assembly of H3.3 and H4 into nucleosomes, BAD, ribosomal protein S6, or MBP (PubMed:21724829). Phosphorylates CASP7, thereby preventing its activity (PubMed:21555521, PubMed:27889207). Additionally, associates with ARHGEF7 and GIT1 to perform kinase-independent functions such as spindle orientation control during mitosis (PubMed:19273597, PubMed:19923322). On the other hand, apoptotic stimuli such as DNA damage lead to caspase-mediated cleavage of PAK2, generating PAK-2p34, an active p34 fragment that translocates to the nucleus and promotes cellular apoptosis involving the JNK signaling pathway (PubMed:9171063, PubMed:12853446, PubMed:16617111). Caspase-activated PAK2 phosphorylates MKNK1 and reduces cellular translation (PubMed:15234964). {ECO:0000269|PubMed:12853446, ECO:0000269|PubMed:15234964, ECO:0000269|PubMed:16617111, ECO:0000269|PubMed:19273597, ECO:0000269|PubMed:19923322, ECO:0000269|PubMed:21177766, ECO:0000269|PubMed:21317288, ECO:0000269|PubMed:21555521, ECO:0000269|PubMed:21724829, ECO:0000269|PubMed:27889207, ECO:0000269|PubMed:33693784, ECO:0000269|PubMed:7744004, ECO:0000269|PubMed:9171063}
PAK2 is also known as KNO2, PAK65, PAKgamma.
