The interleukin-1-stimulated protein kinase that phosphorylates heat shock protein hsp27 is activated by MAP kinase.
In KB cells, interleukin-1 (IL-1), epidermal growth factor and phorbol ester transiently activated both MAP kinase and a serine kinase which phosphorylated the heat shock protein hsp27. Extracts made from IL-1-stimulated KB cells phosphorylated recombinant hsp27, in vitro, on serine residues 78 and 82 which are contained within Arg-X-X-Ser motifs similar to those phosphorylated by the ribosomal protein S6 kinases. Upon size exclusion chromatography, however, hsp27 kinase eluted as a single peak of activity at 50-60 kDa, clearly separated from ribosomal protein S6 kinases. Treatment of partially purified hsp27 kinase with protein phosphatase-2a reduced its activity by 80%. De-phosphorylated hsp27 kinase could be approximately 50% reactivated by a factor present in IL-1-treated cell extracts in the presence of ATP. This factor co-eluted with MAP kinase after partial purification by DEAE-cellulose, phenyl Sepharose, and size exclusion chromatography. Purified sea star p44mpk and recombinant ERK2 MAP kinases were also capable of re-activating hsp27 kinase to a similar extent. These data suggest that hsp27 kinase is downstream from, and probably a direct target of MAP kinase.
Bird
T A
TA
Department of Biochemistry, Immunex Corporation, Seattle, WA 98101.
Schule
H D
HD
Delaney
P
P
de Roos
P
P
Sleath
P
P
Dower
S K
SK
Virca
G D
GD
D000595:Amino Acid Sequence; D004789:Enzyme Activation; D006360:Heat-Shock Proteins / Q000378:metabolism*; D006801:Humans; D007375:Interleukin-1 / Q000494:pharmacology*; D047908:Intracellular Signaling Peptides and Proteins; D007700:Kinetics; D019950:Mitogen-Activated Protein Kinase 1; D008969:Molecular Sequence Data; D010449:Peptide Mapping; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D011505:Protein-Tyrosine Kinases / Q000378:metabolism*; D011994:Recombinant Proteins / Q000378:metabolism; D014407:Tumor Cells, Cultured; D000099190:MAP-Kinase-Activated Kinase 2
D006360:Heat-Shock Proteins; D007375:Interleukin-1; D047908:Intracellular Signaling Peptides and Proteins; D019950:Mitogen-Activated Protein Kinase 1; D017346:Protein Serine-Threonine Kinases; D011505:Protein-Tyrosine Kinases; D011994:Recombinant Proteins; D000099190:MAP-Kinase-Activated Kinase 2