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Stimulation of the T3-T cell receptor-associated Ca2+ influx enhances the activity of the Na+/H+ exchanger in a leukemic human T cell line.

Publication ,  Journal Article
Rosoff, PM; Cantley, LC
Published in: J Biol Chem
November 15, 1985

Three monoclonal antibodies reactive with different structural domains of the T3-T cell receptor complex of the human T cell leukemia line, HPB-ALL, were previously shown to activate a membrane potential-sensitive, La3+-inhibitable Ca2+ influx (Oettgen, H. C., Terhorst, C., Cantley, L. C., and Rosoff, P. M. (1985) Cell 40, 583-590). OKT3 (anti-T3), WT-31 (anti-receptor constant region), and T40/25 (anti-receptor variable region) also enhance the activity of the Na+/H+ exchanger in these cells. The associated rise in pHi was dependent on the presence of external Ca2+ and Na+, was inhibited by dimethylamiloride and La3+, and was maintained for at least 20 min. Phorbol esters, which are co-mitogenic in T cells and activate protein kinase C, also stimulated the exchanger, but by a mechanism not requiring an elevation in cytoplasmic Ca2+; the rise in pHi rapidly peaked and returned to baseline levels within 20 min. Pretreatment with phorbols prevented an increase in pHi by OKT3 although a transient additive effect was observed when the two were added simultaneously. Receptor function was maintained in the presence of phorbol esters as OKT3 still stimulated a Ca2+ influx. These data demonstrate the existence of two interdependent pathways to activate Na+/H+ exchange in T lymphocytes and suggest a pathway of internal regulation of antigen-activated signal transduction.

Duke Scholars

Published In

J Biol Chem

ISSN

0021-9258

Publication Date

November 15, 1985

Volume

260

Issue

26

Start / End Page

14053 / 14059

Location

United States

Related Subject Headings

  • T-Lymphocytes
  • Sodium-Hydrogen Exchangers
  • Receptors, Immunologic
  • Phorbol Esters
  • Leukemia, Lymphoid
  • Lanthanum
  • Hydrogen-Ion Concentration
  • Humans
  • Cell Line
  • Carrier Proteins
 

Published In

J Biol Chem

ISSN

0021-9258

Publication Date

November 15, 1985

Volume

260

Issue

26

Start / End Page

14053 / 14059

Location

United States

Related Subject Headings

  • T-Lymphocytes
  • Sodium-Hydrogen Exchangers
  • Receptors, Immunologic
  • Phorbol Esters
  • Leukemia, Lymphoid
  • Lanthanum
  • Hydrogen-Ion Concentration
  • Humans
  • Cell Line
  • Carrier Proteins