Size and steroid-binding characterization of membrane-associated glucocorticoid receptor in S-49 lymphoma cells

Bahiru Gametchu, Cheryl S. Watson, Dean Pasko

Research output: Contribution to journalArticle

42 Scopus citations

Abstract

The precise mechanism for glucocorticoid-mediated lymphocytolysis is not understood, although it is presumed to be receptor mediated. We have recently presented evidence that this response is mediated by a specialized form of the glucocorticoid receptor (GR) that resides in the plasma membrane (mGR). Confirmation of the previous receptor identification studies in a population of S-49 cells enriched for mGR is now made using another antibody specific for the rodent GR, BUGR-2. The membrane resident receptor could be labeled competitively with the affinity ligand dexamethasone21-mesylate, and Scatchard analysis of whole cell binding revealed that receptor number, but not the affinity for hormone, varied between the mGR-enriched and -deficient cell populations. Steroid specificity displacement analyses showed an order of affinities as follows: triamcinolone acetonide > progesterone > dexamethasone > testosterone = estrogen. Studies of mGR by one- and two-dimensional gel electrophoresis, immunoblot, autoradiography, and density gradients revealed a species with an equivalent size to cytosolic receptor as well as multiple higher molecular weight species, confirming earlier studies. To offer a possible explanation for the nucleic acid origins of the mGR, RNA from the mGR-enriched cells was probed with rat GR cDNA; mGR-enriched cells contained higher levels of GR mRNA. Possible molecular etiologies of larger receptor species in membrane are discussed. (Steroids 56:402-410, 1991).

Original languageEnglish (US)
Pages (from-to)402-410
Number of pages9
JournalSteroids
Volume56
Issue number8
DOIs
StatePublished - Aug 1991

Keywords

  • BUGR monoclonal antibodies
  • RNA
  • hormone specificity
  • lymphocytolysis
  • membrane glucocorticoid receptor
  • steroid

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Endocrinology
  • Pharmacology
  • Clinical Biochemistry
  • Organic Chemistry

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