In vivo phosphorylation of progesterone receptors in the T47D sub co human breast cancer cell line
We have had evidence indicating that human progesterone receptors (PR) are phosphoproteins, and used metabolic labeling with ({sup 35}S)methionine and ({sup 32}P)orthophosphate to study the synthesis, structure, and phosphorylation of PR in T47D{sub co} human breast cancer cells, a cell line extremely rich for PR. Human PR exist as two independent hormone-binding proteins; B-receptors which are triplets in SDS-gels (M{sub r} 114, 117, and 120 kDa), and A-receptors that are a single band (94 kDa). The work presented here documents that human A- and B-receptors are phosphorylated on serine residues in the untransformed state, with phosphate being incorporated into all three bands of the B-proteins. However, a brief ({sup 35}S)methionine pulse shows that both A and B are synthesized as singlets of 94 and 114 kDa, respectively. The B-triplet is formed post-translationally by slow phosphorylation. B-triplet formation, or maturation, can be reversed by treatment with calf alkaline phosphatase or stabilized by the presence of phosphatase inhibitors. Additional ({sup 35}S)labeling studies in the presence of progestins demonstrate that receptors that are 15 min old are able to bind hormone and transform to the tight nuclear binding state.
- Research Organization:
- Colorado Univ., Denver, CO (USA). Health Sciences Center
- OSTI ID:
- 6708604
- Resource Relation:
- Other Information: Thesis (Ph. D.)
- Country of Publication:
- United States
- Language:
- English
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PROGESTERONE
RECEPTORS
PHOSPHORYLATION
ALKALINE PHOSPHATASE
BIOCHEMICAL REACTION KINETICS
ENZYME INHIBITORS
IN VIVO
MAMMARY GLANDS
MAN
METHIONINE
PHOSPHATES
PHOSPHORUS 32
SERINE
SULFUR 35
TRACER TECHNIQUES
TUMOR CELLS
AMINO ACIDS
ANIMAL CELLS
ANIMALS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BODY
CARBOXYLIC ACIDS
CHEMICAL REACTIONS
DAYS LIVING RADIOISOTOPES
DRUGS
ENZYMES
ESTERASES
EVEN-ODD NUCLEI
GLANDS
HORMONES
HYDROLASES
HYDROXY ACIDS
ISOTOPE APPLICATIONS
ISOTOPES
KETONES
KINETICS
LIGHT NUCLEI
LIPOTROPIC FACTORS
MAMMALS
MEMBRANE PROTEINS
NUCLEI
ODD-ODD NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC SULFUR COMPOUNDS
ORGANS
OXYGEN COMPOUNDS
PHOSPHATASES
PHOSPHORUS COMPOUNDS
PHOSPHORUS ISOTOPES
PREGNANES
PRIMATES
PROTEINS
RADIOISOTOPES
REACTION KINETICS
STEROID HORMONES
STEROIDS
SULFUR ISOTOPES
VERTEBRATES
550201* - Biochemistry- Tracer Techniques
550901 - Pathology- Tracer Techniques