Keratin 8 phosphorylation in vitro by cAMP-dependent protein kinase occurs within the amino- and carboxyl-terminal end domains.
We reported earlier that phosphorylation in vitro of keratin filaments reconstituted from rat type I keratin 18 and type II keratin 8 by cAPM-dependent protein kinase induces disassembly of the keratin filament structure. Keratin 8 rather than keratin 18 was the major target of the kinase. We have now identified the sites on rat keratin 8 for cAMP-dependent protein kinase. Sequential analysis of the purified phosphoropeptides, together with the known primary sequence, revealed that four major sites, Ser-12, Ser-23, Ser-36, and Ser-50, and three minor sites, Ser-8, Ser-33, Ser-42, are located in the amino-terminal head domain, while three minor sites, Ser-416, Ser-423 and Ser-425 locate in the carboxyl-terminal tail domain.
Ando
S
S
Biophysics Unit and Laboratory of Biochemistry, Aichi Cancer Center Research Institite, Chikusa-ku, Nagoya, Japan.
Tokui
T
T
Yano
T
T
Inagaki
M
M
D000595:Amino Acid Sequence; D000818:Animals; D002417:Cattle; D002851:Chromatography, High Pressure Liquid; D054746:Cyclic AMP-Dependent Protein Kinase Type II; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism*; D007633:Keratins / Q000737:chemistry / Q000378:metabolism*; D008969:Molecular Sequence Data; D009206:Myocardium / Q000201:enzymology; D010766:Phosphorylation; D051381:Rats
D007633:Keratins; D054746:Cyclic AMP-Dependent Protein Kinase Type II; D017868:Cyclic AMP-Dependent Protein Kinases