Cytosolic double-stranded RNA-dependent protein kinase is likely a dimer of partially phosphorylated Mr = 66,000 subunits.
The work described in this report suggests the existence of two biochemically distinguishable forms of the interferon-inducible, double-stranded RNA-dependent protein kinase. Kinase isolated from the cytosolic fraction (S-100) and the ribosome salt wash fraction of interferon-treated cells differed in their chromatographic properties. S-100 kinase eluted from a gel filtration column with M(r) = 140,000-160,000 and was predominantly anionic in nature, whereas ribosomal kinase eluted with M(r) = 66,000 and was predominantly cationic in nature. Purified preparations of S-100 kinase contained the M(r) = 66,000 subunit, P1, as the only polypeptide present in stoichiometric amounts, and thus the S-100 kinase appears to be a dimer of P1 subunits. Dimerization of the S-100 kinase was dependent on the phosphorylation state of the enzyme. Kinase isolated from S-100 was partially phosphorylated. Dephosphorylation of the S-100 kinase by treatment with alkaline phosphatase resulted in a monomeric form of the enzyme with biochemical characteristics similar to that of the ribosome salt wash kinase.
Langland
J O
JO
Department of Microbiology, Arizona State University, Tempe 85287-2701.
Jacobs
B L
BL
D000469:Alkaline Phosphatase / Q000378:metabolism; D000818:Animals; D015153:Blotting, Western; D002850:Chromatography, Gel; D002852:Chromatography, Ion Exchange; D003600:Cytosol / Q000201:enzymology*; D004790:Enzyme Induction; D007372:Interferons / Q000494:pharmacology; D007739:L Cells; D051379:Mice; D010766:Phosphorylation; D011494:Protein Kinases / Q000096:biosynthesis / Q000737:chemistry / Q000378:metabolism*; D012330:RNA, Double-Stranded / Q000378:metabolism*; D019892:eIF-2 Kinase
D012330:RNA, Double-Stranded; D007372:Interferons; D011494:Protein Kinases; D019892:eIF-2 Kinase; D000469:Alkaline Phosphatase