Skip to main content
OSTI.GOVU.S. Department of Energy Office of Scientific and Technical Information
U.S. Department of Energy
Office of Scientific and Technical Information
 

Insulin receptors mediate growth effects in cultured fetal neurons. II. Activation of a protein kinase that phosphorylates ribosomal protein S6

Journal Article · · Endocrinology; (USA)
;  [1]
  1. Univ. of California-San Diego, La Jolla (USA)
+ Show Author Affiliations

As an initial attempt to identify early steps in insulin action that may be involved in the growth responses of neurons to insulin, we investigated whether insulin receptor activation increases the phosphorylation of ribosomal protein S6 in cultured fetal neurons and whether activation of a protein kinase is involved in this process. When neurons were incubated for 2 h with 32Pi, the addition of insulin (100 ng/ml) for the final 30 min increased the incorporation of 32Pi into a 32K microsomal protein. The incorporation of 32Pi into the majority of other neuronal proteins was unaltered by the 30-min exposure to insulin. Cytosolic extracts from insulin-treated neurons incubated in the presence of exogenous rat liver 40S ribosomes and (gamma-32P)ATP displayed a 3- to 8-fold increase in the phosphorylation of ribosomal protein S6 compared to extracts from untreated cells. Inclusion of cycloheximide during exposure of the neurons to insulin did not inhibit the increased cytosolic kinase activity. Activation of S6 kinase activity by insulin was dose dependent (seen at insulin concentration as low as 0.1 ng/ml) and reached a maximum after 20 min of incubation. Addition of phosphatidylserine, diolein, and Ca2+ to the in vitro kinase reaction had no effect on the phosphorylation of ribosomal protein S6. Likewise, treatment of neurons with (Bu)2cAMP did not alter the phosphorylation of ribosomal protein S6 by neuronal cytosolic extracts. We conclude that insulin activates a cytosolic protein kinase that phosphorylates ribosomal S6 in neurons and is distinct from protein kinase-C and cAMP-dependent protein kinase. Stimulation of this kinase may play a role in insulin signal transduction in neurons.

OSTI ID:
5478769
Journal Information:
Endocrinology; (USA), Journal Name: Endocrinology; (USA) Vol. 125:3; ISSN ENDOA; ISSN 0013-7227
Country of Publication:
United States
Language:
English

Similar Records

Cholecystokinin (CCK) stimulates S6 phosphorylation and induced activation of S6 protein kinase in rat pancreatic acini
Conference · Fri May 01 00:00:00 EDT 1987 · Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States) · OSTI ID:6279434
Nerve growth factor-sensitive S6 kinase in cell-free extracts from PC12 cells
Conference · Thu May 01 00:00:00 EDT 1986 · Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States) · OSTI ID:6859682
Cyclophilin represents a novel class of protein kinases
Conference · Fri May 01 00:00:00 EDT 1987 · Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States) · OSTI ID:5904077

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
AMP
ANIMAL CELLS
ANIMALS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BIOCHEMICAL REACTION KINETICS
BIRDS
BODY
BRAIN
CELL CONSTITUENTS
CELL CULTURES
CELL DIVISION
CENTRAL NERVOUS SYSTEM
CHEMICAL REACTIONS
CHICKENS
DAYS LIVING RADIOISOTOPES
DIGESTIVE SYSTEM
DOSE-RESPONSE RELATIONSHIPS
EMBRYOS
ENZYME ACTIVITY
ENZYMES
FOWL
GLANDS
HORMONES
INSULIN
ISOTOPE APPLICATIONS
ISOTOPES
KINETICS
LIGHT NUCLEI
LIVER
MAMMALS
MEMBRANE PROTEINS
NERVE CELLS
NERVOUS SYSTEM
NUCLEI
NUCLEOTIDES
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
ORGANOIDS
ORGANS
OXYGEN COMPOUNDS
PEPTIDE HORMONES
PHOSPHATES
PHOSPHORUS 32
PHOSPHORUS COMPOUNDS
PHOSPHORUS ISOTOPES
PHOSPHORUS-GROUP TRANSFERASES
PHOSPHORYLATION
PHOSPHOTRANSFERASES
PROTEINS
RADIOISOTOPES
RATS
REACTION KINETICS
RECEPTORS
RIBOSOMES
RODENTS
SOMATIC CELLS
TRACER TECHNIQUES
TRANSFERASES
VERTEBRATES