Regulated phosphorylation of secretory granule membrane proteins of the rat parotid gland

Journal Article · Sun Jul 01 00:00:00 EDT 1990 · American Journal of Physiology; (USA)

OSTI ID:6642889

Marino, C R; Castle, J D; Gorelick, F S ^[1]

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1. Yale Univ. School of Medicine, New Haven, CT (USA)

An antiserum raised against purified rat parotid secretory granule membrane proteins has been used to identify organelle-specific protein phosphorylation events following stimulation of intact cells from the rat parotid gland. After lobules were prelabeled with ({sup 32}P)orthophosphate and exposed to secretagogues, phosphoproteins were immunoprecipitated with the granule membrane protein antiserum, separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and visualized by autoradiography. Parallel studies of stimulated amylase release were performed. Isoproterenol treatment of parotid lobules resulted in an increase in the phosphate content of immunoprecipitable 60- and 72-kDa proteins that correlated with amylase release in a time-dependent manner. Forskolin addition mimicked these effects, but only the isoproterenol effects were reversed by propranolol treatment. To confirm the specificity of the antiserum to the secretory granule membrane fraction, subcellular isolation techniques were employed following in situ phosphorylation. The 60- and 72-kDa phosphoproteins were immunoprecipitated from both a particulate fraction and a purified secretory granule fraction. Furthermore, the extraction properties of both species suggest that they are integral membrane proteins. These findings support the possibility that stimulus-regulated secretion may involve phosphorylation of integral membrane proteins of the exocrine secretory granule.

• OSTI ID: 6642889
• Journal Information: American Journal of Physiology; (USA), Vol. 259; ISSN 0002-9513
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
AMYLASE
SECRETION
MEMBRANE PROTEINS
PHOSPHORYLATION
AUTORADIOGRAPHY
CYTOPLASM
ELECTRON MICROSCOPY
ELECTROPHORESIS
IMMUNOASSAY
MOLECULAR WEIGHT
PHOSPHATES
PHOSPHOPROTEINS
PHOSPHORUS 32
RATS
SALIVARY GLANDS
TIME DEPENDENCE
ANIMALS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BIOASSAY
BODY
CELL CONSTITUENTS
CHEMICAL REACTIONS
DAYS LIVING RADIOISOTOPES
ENZYMES
GLANDS
GLYCOSYL HYDROLASES
HYDROLASES
ISOTOPES
LIGHT NUCLEI
MAMMALS
MICROSCOPY
NUCLEI
O-GLYCOSYL HYDROLASES
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
ORGANS
OXYGEN COMPOUNDS
PHOSPHORUS COMPOUNDS
PHOSPHORUS ISOTOPES
PROTEINS
RADIOISOTOPES
RODENTS
VERTEBRATES
550501* - Metabolism- Tracer Techniques