Human/Mouse PAK3 Alexa Fluor™ Plus 647‑conjugated Antibody

PAK3 (p21-activaed kinase 3; also beta -PAK, PAK3b and oligophrenin-3) is a cytoplasmic 68 kDa member of PAK group I, STE20 subfamily, STE Ser/Thr protein kinase family of molecules. It is expressed in neurons of cortical layers II, III and V, the arcuate nucleus, and neurons in the dorsal raphe plus locus coeruleus. PAK3 mediates axon and dentrite arborization, providing volume to the mass of the CNS. It binds to active GTPases which induce PAK autophosphorylation and activation. Human PAK3(b) is 559 amino acids (aa) in length. It contains one GTPase binding domain (aa 68-128) plus a protein kinase catalytic region (aa 283-534). Acetylation occurs on Lys535, and there are at least three potential phosphorylation sites. Alternate splicing generates three isoform variants. There is a 65 kDa short form that shows a deletion of aa 93-107 (PAK3a), a 69 kDa long form that shows a 21 aa substitution for aa 93-107 (PAK3c), and a 72 kDa very long isoform that contains the aforementioned 21 aa "substitution" inserted onto PAK3b after Thr92 (PAK3cb). PAK3b, c and cb are all constitutively active, and show only modest binding affinity towards GTPases. Over aa 138-255, human PAK3(b) shares 94% aa identity with mouse PAK3(b).