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Titolo:
EVIDENCE FOR CKI AND CKII AT THE CELL-SURFACE
Autore:
WALTER J; KINZEL V; KUBLER D;
Indirizzi:
GERMAN CANC RES CTR,DEPT PATHOCHEM 0210,NEUENHEIMER FELD 280 D-69120 HEIDELBERG GERMANY GERMAN CANC RES CTR,DEPT PATHOCHEM 0210 D-69120 HEIDELBERG GERMANY
Titolo Testata:
Cellular & molecular biology research
fascicolo: 5-6, volume: 40, anno: 1994,
pagine: 473 - 480
SICI:
0968-8773(1994)40:5-6<473:EFCACA>2.0.ZU;2-9
Fonte:
ISI
Lingua:
ENG
Soggetto:
PROTEIN-KINASE-ACTIVITY; GLYCOSYL-PHOSPHATIDYLINOSITOL; ECTOPROTEIN KINASE; INTACT-CELLS; CASEIN; PHOSPHORYLATION; CLEAVAGE; RELEASE; ANCHOR;
Keywords:
CELL SURFACE; PROTEIN PHOSPHORYLATION; ECTOENZYMES; PROTEIN KINASES; CASEIN KINASES; SHEDDING;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Science Citation Index Expanded
Citazioni:
23
Recensione:
Indirizzi per estratti:
Citazione:
J. Walter et al., "EVIDENCE FOR CKI AND CKII AT THE CELL-SURFACE", Cellular & molecular biology research, 40(5-6), 1994, pp. 473-480

Abstract

Ser/Thr-protein kinases at the cell surface (ecto-PK) use physiological concentrations of extracellular ATP for phosphorylation of endogenous cell surface proteins, as well as of soluble protein substrates in the extracellular environment (Kubler et al., 1982, 1989). One abundant ecto-PK component is believed to be a protein kinase CKII since it phosphorylates phosvitin and casein, is sensitive to heparin at low concentrations, and can use both ATP and GTP as cosubstrate. This ecto-PKactivity can be detached from the surface of intact cells through interaction with exogenous substrates, a process termed ''shedding'' (Kubler et al., 1983). This study reports a method for the purification and identification of shedded ecto-PK, Affinity chromatography of the concentrated ecto-PK through a heparin-matrix resolved two phosvitin/casein kinase activities upon elution with a NaCl gradient, termed as peak I and peak II. Relative to the total protein load of the cells employed for ecto-PK shedding, the specific activities increased by a factor of about 10(4) times. The use of peptide substrates specific for CKIand CKII, of ATP and GTP, as well as of antibodies specific for CKII subunit, clearly identified one of the enzymes as a CKI-like entity and the other one as CKII-like. Although the spatial arrangement on the cell surface of the two related ecto-PKs is unknown, their tandem appearance together in the cell supernatant might suggest the possibility of a functional unit.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 02/12/20 alle ore 13:56:20