Casein kinase II-like ectokinase activity on RBL-2H3 cells

Citation
R. Teshima et al., Casein kinase II-like ectokinase activity on RBL-2H3 cells, IMMUNOL LET, 68(2-3), 1999, pp. 369-374
Citations number
20
Categorie Soggetti
Immunology
Journal title
IMMUNOLOGY LETTERS
ISSN journal
01652478 → ACNP
Volume
68
Issue
2-3
Year of publication
1999
Pages
369 - 374
Database
ISI
SICI code
0165-2478(19990601)68:2-3<369:CKIEAO>2.0.ZU;2-F
Abstract
We studied the properties of the ectokinase activity on the outer cell surf aces of RBL-2H3 cells and examined the phosphorylation of exogenous substra tes to clarify the substrate specificity of the ectokinases on RBL-2H3 cell s. Among the several protein substrates tested, casein was the most strongl y phosphorylated with [gamma-P-32]ATP, and the net incorporation of P-32 in to casein was 0.65 pmol P/50 mu g/10(6) cells. Casein kinase II peptide was also phosphorylated with [y-P-32]ATP. The phosphorylation of casein and ca sein kinase II peptide was almost completely inhibited by the addition of 3 mu g/ml of cell-impermeable K252b. Phosphorylation of casein and casein ki nase II peptide was also observed by [gamma-P-32]GTP. Western blot analysis using anti-casein kinase II antibody revealed a 44-kDa casein kinase band in the membrane fraction and Fc epsilon RI complexes. The immunofluorescenc e microscopic analysis using anti-casein kinase II antibody showed the exis tence of casein kinase II on the surface of the cells. This is the first re port about the existence of ectokinase on mast cells. (C) 1999 Elsevier Sci ence B.V. All rights reserved.