Phosphorylation of the catalytic subunit of type‐1 protein phosphatase by the v‐abl tyrosine kinase

FEBS Letters

Villa-Moruzzi, Emma²  Zonca, Paolo Dalla¹  Crabb, John W.³ 

[1] Department of Biomedical Sciences and Oncology, University of Torino, 10126 Torino, Italy;Department of Biomedicine, University of Pisa, 56126 Pisa, Italy;W. Alton Jones Cell Science Center, Lake Placid, NY 12946, USA

关键词: Protein phosphatase;    Protein kinase;    Tyrosine kinase;    Phosphorylation;    TPCK;    N-tosyl-L-phenylalanine chloromethyl ketone;    PMSF;    phenylmethylsulfonylfluoride;    BSA;    bovine serum albumin;    SDS;    sodium dodecylsulfate;    PP;    protein serine/threonine phosphatase assayed here as phosphorylase phosphatase;    PP1;    protein phosphatase of type-1;    E;    catalytic subunit of PP1;    Ea;    active E;    Ea et;    cytosolic Ea purified by a procedure that includes ethanol precipitation;    Ea G;    catalytic subunit of PP1 purified from the glycogen particles;    Ei;    inactive E isolated from the 70 kDa E1-12 cytosolic complex;    Ea Mn;    obtained from E1 following activation by Mn2+;    Ea FA;    Ea isolated from the 70 kDa cytosolic complex that had been activated by the kinase FA/GSK3;    obtained from E1 following activation by Mn2+;    Ea FA;    Ea isolated from the 70 kDa cytosolic complex that had been activated by the kinase FA/GSK3;    12;    inhibitory-2 of PP1;    FA/GSK3;    protein kinase that activates PP1;    also called glycogen synthase kinase-3;   

DOI  :  10.1016/0014-5793(91)81154-Z

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The catalytic subunit of type-1 protein phosphatase (PP1) was phosphorylated by the tyrosine kinase v-abl as follows: (i) cytosolic PP1 was phosphorylated more (0.73 mol/mol) than PP1 obtained from the glycogen particles (0.076 mol/mol), while free catalytic subunit isolated in the active or inactive form from cytosolic PP1 was phosphorylated even less and catalytic subunit complexed with inhibitory was not phosphorylated; (ii) phosphorylation stoichiometry was dependent on the concentration of PP1 and 3 h incubation at 30°C was required for maximal phosphorylation; (iii) phosphorylation was on a tyrosine residue located in the C-terminal region of PP1 which is lost during proteolysis; (iv) phosphorylation did not affect enzyme activity but allowed conversion from the active to the inactive form upon incubation with inhibitory of a PP1 form that in its dephospho-form did not convert.

【 授权许可】

Unknown