Glucocorticoid-regulated and constitutive trafficking of proteolytically processed cell surface-associated glycoproteins in wild type and variant rat hepatoma cells
- Univ. of California, Berkeley (USA)
Glucocorticoids regulate the trafficking of mouse mammary tumor virus (MMTV) glycoproteins to the cell surface in the rat hepatoma cell line M1.54, but not in the immunoselected sorting variant CR4. To compare the localization of MMTV glycoproteins to another proteolytically processed glycoprotein, both wild type M1.54 cells and variant CR4 cells were transfected with a human insulin receptor (hIR) expression vector, pRSVhIR. The production of cell surface hIR was monitored in dexamethasone-treated and -untreated wild type M1.54 and variant CR4 cells by indirect immunofluorescence, direct plasma membrane immunoprecipitation, and by (125I) insulin binding. In both wild type and variant rat hepatoma cells, hIR were localized at the cell surface in the presence or in the absence of 1 microM dexamethasone. In contrast, the glucocorticoid-regulated trafficking of cell surface MMTV glycoproteins occurred only in wild type M1.54 cells. We conclude that the hIR, which undergoes posttranslational processing reactions similar to MMTV glycoproteins, does not require glucocorticoids to be transported to the plasma membrane and is representative of a subset of cell surface glycoproteins whose trafficking is constitutive in rat hepatoma cells. Thus, MMTV glycoproteins and hIR provide specific cell surface markers to characterize the glucocorticoid-regulated and constitutive sorting pathways.
- OSTI ID:
- 7195070
- Journal Information:
- Molecular Endocrinology; (USA), Vol. 3:10; ISSN 0888-8809
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
GLUCOCORTICOIDS
BIOLOGICAL FUNCTIONS
GLYCOPROTEINS
BIOLOGICAL LOCALIZATION
INSULIN
RECEPTORS
BIOCHEMICAL REACTION KINETICS
BIOLOGICAL PATHWAYS
CELL MEMBRANES
DEXAMETHASONE
EXPERIMENTAL NEOPLASMS
FLUORESCENCE
HEPATOMAS
IODINE 125
LIVER
MAMMARY GLANDS
MAN
MEMBRANE TRANSPORT
MICE
RATS
TRACER TECHNIQUES
TUMOR CELLS
VIRUSES
ADRENAL HORMONES
ANIMAL CELLS
ANIMALS
BETA DECAY RADIOISOTOPES
BODY
CELL CONSTITUENTS
CORTICOSTEROIDS
DAYS LIVING RADIOISOTOPES
DIGESTIVE SYSTEM
DISEASES
ELECTRON CAPTURE RADIOISOTOPES
FUNCTIONS
GLANDS
HORMONES
HYDROXY COMPOUNDS
INTERMEDIATE MASS NUCLEI
IODINE ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
KETONES
KINETICS
LUMINESCENCE
MAMMALS
MEMBRANE PROTEINS
MEMBRANES
MICROORGANISMS
NEOPLASMS
NUCLEI
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
ORGANS
PARASITES
PEPTIDE HORMONES
PREGNANES
PRIMATES
PROTEINS
RADIOISOTOPES
REACTION KINETICS
RODENTS
STEROIDS
VERTEBRATES
550201* - Biochemistry- Tracer Techniques