R. Jakobi et al., MOLECULAR-CLONING AND SEQUENCING OF THE CYTOSTATIC-G PROTEIN-ACTIVATED PROTEIN-KINASE PAK-I, The Journal of biological chemistry, 271(11), 1996, pp. 6206-6211
The serine/threonine protein kinase PAK I ((p) under bar 21-(a) under
bar ctivated protein (k) under bar inase), a ubiquitous multipotential
protein kinase of 58-60 kDa, has been shown to have cytostatic proper
ties. Data from our laboratory show that PAK I is highly active in ooc
ytes and quiescent and serum starved cells, and injection of active PA
K I into one blastomere of two-cell frog embryos inhibits cleavage of
the injected blastomere. To clone the cDNA encoding PAK I, purified pe
ptides from rabbit PAK I were sequenced, degenerate oligonucleotides w
ere used to isolate PAK I clones from a rabbit spleen library, and the
5'-terminus was obtained by polymerase chain reaction. The entire cDN
A sequence extends over 4471 nucleotides, with an open reading frame f
or a protein of 524 residues and a 3'-noncoding region of 2826 nucleot
ides. Clones with the same open reading frame but with 3'-noncoding re
gions of 1055 and 2478 nucleotides were isolated, suggesting the gener
ation of different transcripts by alternative termination of transcrip
tion. The amino acid sequence of PAK I shows high homology to the pal-
activated protein kinases from human placenta and rat brain and to yea
st STE20. PAK I is activated by Cdc42(GTP). The PAK enzymes have been
proposed to regulate the stress-activated protein kinase (also known a
s the Jun kinase) signaling pathway (Coso, O. A., Chiariello, M., Yu,
J.-C., Teramoto, H., Crespo, P., Xu, N., Miki, T., and Gutkind, J. S.
(1995) Cell 81, 1137-1146; Minden, A., Lin, A., Claret, F.-X., Abo, A.
, and Karin, M. (1995) Cell 81, 1147-1157).