• Rubin, Charles S. (PI)

Project: Research project

Project Details


The objective of this proposal is to investigate the viochemical mechanism
of action of cyclic AMP-mediated hormones and insulin in a cultured cell
line uniquely suited to these studies. In Section I we will analyze the
mechanism by which adenylate cyclase becomes coupled to the Beta-adrenergic
receptor during differentiation. We will systematically quantiate the
Beta-adrenergic receptor (R), the guanine nucleotide regulatory protein
(G/F) and the catalytic component of the cylcase throughout the
differentiation program, establish the kinetics of appearance of
catecholamine- and/or guanine nucleotide-stimulated adenylate cyclase
activities and determine whether the expression of catecholamine-sensitive
adenylate cyclase is directly coordinated with the accumulation of
regulatory components (G/F and R). In Section II, we utilize the
developmental acquisition of high affinity insulin receptors by the 3T3-Ll
cells to study the structure and regulation of insulin receptor content
using antibodies to the receptor, a cross-linking reagent that can
selectively covalently label the receptor with [125I]-insulin, and a new
procedure for reversibly removing cell surface insulin receptor activity
with chymotrypsin. The information obtained will relate tot he molecular
structure of the insulin receptor system during differentiation and the
role of the "latent" receptor pool in maintaining the complement of cell
surface insulin receptors. In part III we investigate the effect of
cAMP-mediated and insulin-promoted phosphorylation of a key lipogenic
enzyme, ATP citrate lyase, that is found induced during 3T3-Ll
differentiation. We will develop a site-specific assay for
insulin-mediated protein phosphorylation, purify lyase-specific protein
kinase and phosphatase and attempt to use the lyase in an in vitro system
to study the biochemical mechanism of insulin action.
Effective start/end date9/1/7711/30/86


  • National Institutes of Health


  • Medicine(all)


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