Human PAK4 kinase (UniProt: O96013; NCBI: NM_005884) belongs to a family of p21-activated kinases. These serine/threonine kinases are regulated by the small GTP binding proteins Cdc42 and Rac and have been implicated in a wide range of biological activities. PAK4 is a mediator of filopodia formation and may play a role in the reorganization of the actin cytoskeleton. The calculated mass is 33,309. PAK4KD is fully phosphorylated at S474 with a measured mass of 33,389 (1P).