In vivo phosphorylation of progesterone receptors in the T47D sub co human breast cancer cell line

Thesis/Dissertation · Sun Jan 01 04:00:00 EST 1989

OSTI ID:6708604

Sheridan, P L

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
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
550901 -- Pathology-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ALKALINE PHOSPHATASE
AMINO ACIDS
ANIMAL CELLS
ANIMALS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BIOCHEMICAL REACTION KINETICS
BODY
CARBOXYLIC ACIDS
CHEMICAL REACTIONS
DAYS LIVING RADIOISOTOPES
DRUGS
ENZYME INHIBITORS
ENZYMES
ESTERASES
EVEN-ODD NUCLEI
GLANDS
HORMONES
HYDROLASES
HYDROXY ACIDS
IN VIVO
ISOTOPE APPLICATIONS
ISOTOPES
KETONES
KINETICS
LIGHT NUCLEI
LIPOTROPIC FACTORS
MAMMALS
MAMMARY GLANDS
MAN
MEMBRANE PROTEINS
METHIONINE
NUCLEI
ODD-ODD NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC SULFUR COMPOUNDS
ORGANS
OXYGEN COMPOUNDS
PHOSPHATASES
PHOSPHATES
PHOSPHORUS 32
PHOSPHORUS COMPOUNDS
PHOSPHORUS ISOTOPES
PHOSPHORYLATION
PREGNANES
PRIMATES
PROGESTERONE
PROTEINS
RADIOISOTOPES
REACTION KINETICS
RECEPTORS
SERINE
STEROID HORMONES
STEROIDS
SULFUR 35
SULFUR ISOTOPES
TRACER TECHNIQUES
TUMOR CELLS
VERTEBRATES