Protein kinase C and an endogenous substrate associated with adenohypophyseal secretory granules

Judith L Turgeon, R. H. Cooper

Research output: Contribution to journalArticle

21 Citations (Scopus)

Abstract

Secretory granules isolated from anterior pituitary glands were examined for Ca2+/phospholipid-dependent protein kinase (protein kinase C) activity as well as the occurrence of granule-associated substrate proteins. Sheep adenohypophyses were fractionated by differential and sucrose-density-gradient centrifugation to yield a granule fraction enriched for luteinizing-hormone (lutropin)-containing secretory granules. Marker-enzyme analysis showed no detectable cytosolic contamination, although there were small amounts of plasma membranes (2-4%) and lysosomes (4-6%) associated with the preparation. As determined by histone-H1 phosphorylation after DEAE-cellulose DE-52 chromatography, protein kinase C activity with a marked dependence on Ca2+ and lipid (4-fold increase in their presence) was evident in the secretory-granule fraction. Phosphorylation in vitro of the secretory-granule fraction by endogenous and exogenous protein kinase C revealed a protein of M(r) 36,000, which by two-dimensional SDS/polyacrylamide-gel electrophoresis showed multiple sites of phosphorylation. The M(r)-36,000 protein was not found in cytosolic or plasma-membrane fractions and was not phosphorylated by the catalytic subunit of cyclic AMP-dependent protein kinase. Several secretory-granule proteins served as substrates for the catalytic subunit, the most prominent of which were of M(r) 63,000, 23,000 and 21,000. From these data, we suggest that phosphorylation of secretory-granule-associated proteins by protein kinase C and by cyclic AMP-dependent protein kinase may be important in secretion regulation in the anterior pituitary gland.

Original languageEnglish (US)
Pages (from-to)53-61
Number of pages9
JournalBiochemical Journal
Volume237
Issue number1
StatePublished - 1986

Fingerprint

Secretory Vesicles
Phosphorylation
Protein Kinase C
Anterior Pituitary Gland
Substrates
Cell membranes
Luteinizing Hormone
Proteins
Cyclic AMP-Dependent Protein Kinase Catalytic Subunits
DEAE-Cellulose
Cell Membrane
Centrifugation
Cyclic AMP-Dependent Protein Kinases
Chromatography
Electrophoresis
Density Gradient Centrifugation
Histones
Protein Kinases
Electrophoresis, Gel, Two-Dimensional
Sucrose

ASJC Scopus subject areas

  • Biochemistry

Cite this

Protein kinase C and an endogenous substrate associated with adenohypophyseal secretory granules. / Turgeon, Judith L; Cooper, R. H.

In: Biochemical Journal, Vol. 237, No. 1, 1986, p. 53-61.

Research output: Contribution to journalArticle

@article{53298ffb314f415082ed7895f0fd715d,
title = "Protein kinase C and an endogenous substrate associated with adenohypophyseal secretory granules",
abstract = "Secretory granules isolated from anterior pituitary glands were examined for Ca2+/phospholipid-dependent protein kinase (protein kinase C) activity as well as the occurrence of granule-associated substrate proteins. Sheep adenohypophyses were fractionated by differential and sucrose-density-gradient centrifugation to yield a granule fraction enriched for luteinizing-hormone (lutropin)-containing secretory granules. Marker-enzyme analysis showed no detectable cytosolic contamination, although there were small amounts of plasma membranes (2-4{\%}) and lysosomes (4-6{\%}) associated with the preparation. As determined by histone-H1 phosphorylation after DEAE-cellulose DE-52 chromatography, protein kinase C activity with a marked dependence on Ca2+ and lipid (4-fold increase in their presence) was evident in the secretory-granule fraction. Phosphorylation in vitro of the secretory-granule fraction by endogenous and exogenous protein kinase C revealed a protein of M(r) 36,000, which by two-dimensional SDS/polyacrylamide-gel electrophoresis showed multiple sites of phosphorylation. The M(r)-36,000 protein was not found in cytosolic or plasma-membrane fractions and was not phosphorylated by the catalytic subunit of cyclic AMP-dependent protein kinase. Several secretory-granule proteins served as substrates for the catalytic subunit, the most prominent of which were of M(r) 63,000, 23,000 and 21,000. From these data, we suggest that phosphorylation of secretory-granule-associated proteins by protein kinase C and by cyclic AMP-dependent protein kinase may be important in secretion regulation in the anterior pituitary gland.",
author = "Turgeon, {Judith L} and Cooper, {R. H.}",
year = "1986",
language = "English (US)",
volume = "237",
pages = "53--61",
journal = "Biochemical Journal",
issn = "0264-6021",
publisher = "Portland Press Ltd.",
number = "1",

}

TY - JOUR

T1 - Protein kinase C and an endogenous substrate associated with adenohypophyseal secretory granules

AU - Turgeon, Judith L

AU - Cooper, R. H.

PY - 1986

Y1 - 1986

N2 - Secretory granules isolated from anterior pituitary glands were examined for Ca2+/phospholipid-dependent protein kinase (protein kinase C) activity as well as the occurrence of granule-associated substrate proteins. Sheep adenohypophyses were fractionated by differential and sucrose-density-gradient centrifugation to yield a granule fraction enriched for luteinizing-hormone (lutropin)-containing secretory granules. Marker-enzyme analysis showed no detectable cytosolic contamination, although there were small amounts of plasma membranes (2-4%) and lysosomes (4-6%) associated with the preparation. As determined by histone-H1 phosphorylation after DEAE-cellulose DE-52 chromatography, protein kinase C activity with a marked dependence on Ca2+ and lipid (4-fold increase in their presence) was evident in the secretory-granule fraction. Phosphorylation in vitro of the secretory-granule fraction by endogenous and exogenous protein kinase C revealed a protein of M(r) 36,000, which by two-dimensional SDS/polyacrylamide-gel electrophoresis showed multiple sites of phosphorylation. The M(r)-36,000 protein was not found in cytosolic or plasma-membrane fractions and was not phosphorylated by the catalytic subunit of cyclic AMP-dependent protein kinase. Several secretory-granule proteins served as substrates for the catalytic subunit, the most prominent of which were of M(r) 63,000, 23,000 and 21,000. From these data, we suggest that phosphorylation of secretory-granule-associated proteins by protein kinase C and by cyclic AMP-dependent protein kinase may be important in secretion regulation in the anterior pituitary gland.

AB - Secretory granules isolated from anterior pituitary glands were examined for Ca2+/phospholipid-dependent protein kinase (protein kinase C) activity as well as the occurrence of granule-associated substrate proteins. Sheep adenohypophyses were fractionated by differential and sucrose-density-gradient centrifugation to yield a granule fraction enriched for luteinizing-hormone (lutropin)-containing secretory granules. Marker-enzyme analysis showed no detectable cytosolic contamination, although there were small amounts of plasma membranes (2-4%) and lysosomes (4-6%) associated with the preparation. As determined by histone-H1 phosphorylation after DEAE-cellulose DE-52 chromatography, protein kinase C activity with a marked dependence on Ca2+ and lipid (4-fold increase in their presence) was evident in the secretory-granule fraction. Phosphorylation in vitro of the secretory-granule fraction by endogenous and exogenous protein kinase C revealed a protein of M(r) 36,000, which by two-dimensional SDS/polyacrylamide-gel electrophoresis showed multiple sites of phosphorylation. The M(r)-36,000 protein was not found in cytosolic or plasma-membrane fractions and was not phosphorylated by the catalytic subunit of cyclic AMP-dependent protein kinase. Several secretory-granule proteins served as substrates for the catalytic subunit, the most prominent of which were of M(r) 63,000, 23,000 and 21,000. From these data, we suggest that phosphorylation of secretory-granule-associated proteins by protein kinase C and by cyclic AMP-dependent protein kinase may be important in secretion regulation in the anterior pituitary gland.

UR - http://www.scopus.com/inward/record.url?scp=0022516482&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0022516482&partnerID=8YFLogxK

M3 - Article

VL - 237

SP - 53

EP - 61

JO - Biochemical Journal

JF - Biochemical Journal

SN - 0264-6021

IS - 1

ER -