Purification and characterisation of p99, a nuclear modulator of protein phosphatase 1 activity

FEBS Letters

Lyon, Carol E²  Lamond, Angus I²  Kreivi, Jan-Peter¹  Morrice, Nick A³  Cohen, Philip³  Trinkle-Mulcahy, Laura³ 

[1] Medical Immunology and Microbiology, BMC, Uppsala University, Box 582, S-751 23 Uppsala, Sweden;Department of Biochemistry, The University, Dundee, DD1 4HN, Scotland, UK;Medical Research Council Protein Phosphorylation Unit, Department of Biochemistry, The University, Dundee, DD1 4HN, Scotland, UK

关键词: Protein phosphatase 1;    Nucleus;    Immunocytochemistry;    Cell regulation;   

DOI  :  10.1016/S0014-5793(97)01485-3

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

We have purified a form of protein phosphatase 1 (PP1) from HeLa cell nuclei, in which the phosphatase is complexed to a regulatory subunit termed p99. We report here the cloning and characterisation of the p99 component. p99 mRNA is widely expressed in human tissues and immunofluorescence analysis with anti-p99 antibodies showed a punctate nucleoplasmic staining with additional accumulations within the nucleolus. The C-terminus of p99 contains seven RGG RNA-binding motifs, followed by eleven decapeptide repeats containing six or more of the following conserved residues (GHRPHEGPGG), and finally a putative zinc finger domain. Recombinant p99 suppresses the phosphorylase phosphatase activity of PP1 by >90% and the canonical PP1-binding motif on p99 (residues 396–401) is unusual in that the phenylalanine residue is replaced by tryptophan.

【 授权许可】

Unknown