Studies on the arrangement of glucocorticoid receptors in the plasma membrane of S-49 lymphoma cells

Bahiru Gametchu, Cheryl S. Watson, Charles C.Y. Shih, Berhane Dashew

Research output: Contribution to journalArticle

36 Scopus citations

Abstract

The presence of glucocorticoid receptors is required for glucocorticoid-mediated lymphocytolysis to take place. However, the explicit mechanism of involvement of this receptor continues to be debated. We have recently presented evidence that this response is mediated by a specialised form of the glucocorticoid receptor that resides in the plasma membrane (mGR). Using sequential cell separation techniques ("immunopanning," fluorescent cell sorting, and soft agar cloning), a resultant population of membrane receptor-enriched cells have remained stable and provided material for further analysis. The mGR patching and capping phenomenon originally observed with fluoresceinated monoclonal antibody techniques was verified here with electron micrographic analysis using colloidal gold-conjugated antibody. Using 3H-labeled monoclonal antibody, a radioimmunoassay for membrane receptors was developed. Trypsin treatment removed the membrane receptor antigenic site from the surface of cells. Peptide mapping of receptor purified from plasma membranes reveals several trypsin and α-chymotrypsin cleavage sites. Larger fragments resulted from cleavage of the membrane receptor of cells enriched for mGR versus those found in cells depleted of the membrane form, although most of the resulting fragments are shared by the two forms. Confirmation of previous studies correlating membrane receptor with the mechanism of glucocorticoid sensitivity is now extended to include elimination of the lymphocytolysis effect in membrane receptor-stripped (trypsinized) S-49 cells. (Steroids 56:411-419, 1991).

Original languageEnglish (US)
Pages (from-to)411-419
Number of pages9
JournalSteroids
Volume56
Issue number8
DOIs
StatePublished - Aug 1991

    Fingerprint

Keywords

  • BUGR-1
  • BUGR-2 monoclonal antibodies
  • electron microscopy
  • lymphocytolysis
  • membrane glucocorticoid receptor
  • steroid
  • trypsin
  • α-chymotrypsin

ASJC Scopus subject areas

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

Cite this