Modulation of insulin responses in cultured cells by calmodulin
The main impetus of this work was to analyze the possible association of Ca{sup ++}/calmodulin with the {beta} subunit tyrosine kinase of the insulin receptor in whole cells, and to correlate this association to insulin dependent biological responses. Initial in vitro assays with IM-9 lymphocyte receptor preparations demonstrated that calmodulin augments insulin-stimulated receptor autophosphorylation in a calcium dependent manner. Furthermore, the specific calmodulin inhibitors calmidazolium and agent W-7 were effective at inhibiting insulin stimulated receptor autophosphorylation at concentrations reported to inhibit other calmodulin regulated systems. Utilizing the insulin-responsive cultured muscle cell line BC3H-1, we have investigated the effects of these calmodulin antagonists on insulin receptor autophosphorylation, insulin-stimulated DNA synthesis, and insulin-stimulated hexose uptake in intake in intact cells. Confluent BC3H-1 myocytes were assayed for responsiveness to insulin in the presence and absence of increasing concentrations of calmidazolium or W-7 at 37{degree}C. Insulin-stimulated receptor tyrosine autophosphorylation of the 95 kDa {beta}-subunit was inhibited by both agents with IC{sub 50} values for each of {approximately}30 {mu}M. {sup 3}H-thymidine incorporation into DNA was also inhibited with an IC{sub 50} value for each of 20-30 {mu}M. Insulin-stimulated {sup 3}H-2-deoxyglucose uptake was not specifically affected by calmidazolium and demonstrated inhibition by W-7 only at concentrations indication that the effect is not modulated by a calmodulin dependent mechanism.
- Research Organization:
- University of South Florida, Tampa, FL (USA)
- OSTI ID:
- 6172575
- Resource Relation:
- Other Information: Thesis (Ph. D.)
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
CALMODULIN
BIOCHEMICAL REACTION KINETICS
INSULIN
RECEPTORS
PHOSPHORYLATION
CALCIUM COMPOUNDS
CELL CULTURES
DNA REPLICATION
GLUCOSE
HEXOSES
INHIBITION
LYMPHOCYTES
MUSCLES
THYMIDINE
TRACER TECHNIQUES
TRITIUM COMPOUNDS
TYROSINE
UPTAKE
ALDEHYDES
ALKALINE EARTH METAL COMPOUNDS
AMINO ACIDS
ANIMAL CELLS
AZINES
BIOLOGICAL MATERIALS
BLOOD
BLOOD CELLS
BODY FLUIDS
CARBOHYDRATES
CARBOXYLIC ACIDS
CHEMICAL REACTIONS
CONNECTIVE TISSUE CELLS
HETEROCYCLIC COMPOUNDS
HORMONES
HYDROGEN COMPOUNDS
HYDROXY ACIDS
ISOTOPE APPLICATIONS
KINETICS
LEUKOCYTES
MATERIALS
MEMBRANE PROTEINS
MONOSACCHARIDES
NUCLEIC ACID REPLICATION
NUCLEOSIDES
NUCLEOTIDES
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PEPTIDE HORMONES
PROTEINS
PYRIMIDINES
REACTION KINETICS
RIBOSIDES
SACCHARIDES
SOMATIC CELLS
550201* - Biochemistry- Tracer Techniques