Isoform composition and stoichiometry of the approx. 90-kDa heat shock protein associated with glucocorticoid receptors

Journal Article · Sun May 15 04:00:00 EDT 1988 · J. Biol. Chem.; (United States)

OSTI ID:6838345

Mendel, D B; Orti, E

The authors observed that the approx. 90-kDa non-steroid-binding component of nonactivated glucocorticoid receptors purified from WEHI-7 mouse thymoma cells (which has been identified as the approx. 90-kDa heat shock protein) consistently migrates as a doublet during polyacrylamide gel electrophoresis under denaturing and reducing conditions. It has recently been reported that murine Meth A cells contain a tumor-specific transplantation antigen (TSTA) which is related or identical to the approx. 90-kDa heat shock protein. The observation that TSTA and the approx. 90-kDa heat shock protein isolated from these cells exists as two isoforms of similar molecular mass and charge has suggested that the doublet observed is also due to the existence of two isoforms. They have therefore conducted this study to determine whether TSTA and the approx. 90-kDa component of glucocorticoid receptors are indeed related, to establish whether the receptor preferentially binds one isoform of the approx. 90-kDa heat shock protein, and to investigate the stoichiometry of the nonactivated receptor complex. They used the BuGr1 and AC88 monoclonal antibodies to purify, respectively, receptor-associated and free approx. 90-kDa heat shock protein from WEHI-7 cells grown for 48 h with (/sup 35/S)methionine to metabolically label proteins to steady state. The long-term metabolic labeling approach has also enabled them to directly determine that the purified non-activated glucocorticoid receptor contains a single steroid-binding protein and two approx. 90-kDa non-steroid-binding subunits. The consistency with which a approx. 1:2 stoichiometric ratio of steroid binding to approx. 90-kDa protein is observed supports the view that the approx. 90-kDa heat shock protein is a true component of nonactivated glucocorticoid-receptor complexes.

• Research Organization: Dartmouth Medical School, Hanover, NH (USA)
• OSTI ID: 6838345
• Journal Information: J. Biol. Chem.; (United States), Journal Name: J. Biol. Chem.; (United States) Vol. 263:14; ISSN JBCHA
• Country of Publication: United States
• Language: English

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550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ADRENAL HORMONES
AMINO ACIDS
ANIMAL CELLS
ANIMALS
ANTIBODIES
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
CARBOXYLIC ACIDS
CORTICOSTEROIDS
DAYS LIVING RADIOISOTOPES
DRUGS
ELECTROPHORESIS
EVEN-ODD NUCLEI
GLUCOCORTICOIDS
HYDROXY COMPOUNDS
ISOTOPE APPLICATIONS
ISOTOPES
KETONES
LIGHT NUCLEI
LIPOTROPIC FACTORS
MAMMALS
MEMBRANE PROTEINS
METHIONINE
MICE
MOLECULAR STRUCTURE
MONOCLONAL ANTIBODIES
NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC SULFUR COMPOUNDS
PREGNANES
PROTEINS
RADIOISOTOPES
RECEPTORS
RODENTS
STEROIDS
STOICHIOMETRY
SULFUR 35
SULFUR ISOTOPES
TRACER TECHNIQUES
TUMOR CELLS
VERTEBRATES