A specific phosphoprotein phosphatase acts on histone H1 phosphorylated by protein kinase C.
A phosphohistone phosphatase from rat liver cytosol acts specifically on histone H1 that is phosphorylated with the Ca2+-phospholipid-dependent protein kinase (protein kinase C). The apparent Km for 32P-labeled H1 is 1 microM; other histones or cytosolic proteins phosphorylated with protein kinase C or with cyclic AMP-dependent protein kinase are poor substrates for the phosphatase. The enzyme has been partially purified by gel-permeation chromatography and by utilizing a high-performance liquid chromatography ion-exchange column. The physical properties of this enzyme include a Stokes radius of 5.0 nm, a sedimentation coefficient (s20,w) of 7.0 S, and a Mr of 150,000. The detection of protein kinase as well as the specific phosphohistone phosphatase in purified rat liver nuclei suggests a physiologic role for a histone H1 phosphorylation-dephosphorylation cycle mediated by protein kinase C and the corresponding phosphohistone phosphatase.
D000818:Animals; D002467:Cell Nucleus / Q000201:enzymology; D002851:Chromatography, High Pressure Liquid; D003600:Cytosol / Q000201:enzymology; D006657:Histones / Q000302:isolation & purification / Q000378:metabolism*; D007700:Kinetics; D008099:Liver / Q000201:enzymology*; D008297:Male; D008970:Molecular Weight; D010749:Phosphoprotein Phosphatases / Q000302:isolation & purification / Q000378:metabolism*; D010766:Phosphorylation; D011493:Protein Kinase C; D011494:Protein Kinases / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains
D006657:Histones; D011494:Protein Kinases; D011493:Protein Kinase C; D010749:Phosphoprotein Phosphatases