DIRECT INVOLVEMENT OF INTRACELLULAR CA2+ TRANSPORT ATPASE IN THE DEVELOPMENT OF

2020-03-26 15:55:42

resistance cells tg ATPase MED

责任者: HUSSAIN, A;GARNETT, C;KLEIN, MG;TSAIWU, JJ;SCHNEIDER, MF;INESI, G 单位: UNIV MARYLAND,CTR CANC,SCH MED,DEPT MED,DIV ONCOL,BALTIMORE,MD.;VET ADM MED CTR,BALTIMORE,MD 21201. 来源出处: JOURNAL OF BIOLOGICAL CHEMISTRY, v 270, MAY 19 1995, p 12140- 12146 摘要: Thapsigargin (TG), a specific inhibitor of intracellular Ca2+ transport ATPases (SERCA), inhibits cell proliferation when added to culture media in the nanomolar concentration range, However, long term exposure to gradually increasing concentrations of TG induces resistance to TG inhibition in both the parental Chinese hamster lung fibroblast DC-3F and a subline derived from it via transfection and stable expression of a full-length cDNA encoding avian SERCA1 ATPase (DC-3F/Ca cells), TG resistance develops in parallel with selection of cells expressing higher levels of the endogenous SERCA2 as well as of the exogenous transfected SERCA1 ATPase, whose Ca2+ transport function can be studied in situ by imaging techniques and following isolation in microsomal fractions, Microsomes isolated from resistant cells contain two functionally distinct populations of ATPases: a population that is inhibited by stoichiometric titration with TG, and a population displaying resistance to inhibition even when TG exceeds the enzyme stoichiometry, It is apparent that resistance to TG develops in parallel with (a) selection of cells expressing high levels of SERCA ATPases, and (b) selection of an ATPase that is resistant to TG. 关键词: ION EXCHANGE; FLOW INJECTION; SPECTROPHOTOMETRY; CADMIUM; TERNARY COMPLEX; FOODSTUFFS COMPLEX; FOODSTUFFS; SARCOPLASMIC-RETICULUM; INHIBITION; CELLS; CA-2+-ATPASE; CA2+-ATPASE; EXPRESSION; PUMP EXPRESSION; PUMP