PAK1 and PAK2 phosphorylate and inactivate MYLK (MLCK), a myosin light chain kinase. It is assumed that PAK1 phosphorylates the same sites as PAK2. MYLK serine residues phosphorylated by PAK2 were determined using rabbit recombinant MYLK and human PAK2. Rabbit MYLK serines S439 and S991 are conserved in human MYLK and match S1208 and S1759 (Sanders et al. 1999, Goeckeler et al. 2000). Please note that the recombinant rabbit MYLK sequence is shorter than the canonical human MYLK sequence and corresponds to human MYLK transcription isoforms that lack the first 922 amino acids present in the canonical MYLK isoform.
de Lanerolle, P