AMINO ACID CONTROL OF PLASMA MEMBRANE PROTEIN SYNTHESIS

My most recent research experience with Dr. Kilberg, the sponsor
of this project proposal, led to the focusing of my efforts on the
study of the cellular responses to nutrient deprivation. We have
identified an integral plasma membrane protein for which
biosynthesis is induced in response to amino acid starvation. The
protein is present in the plasma membrane of cultured Fao hepatoma
cells and has a molecular weight of 45 kD and an isoelectric point
of 5.2 (HPM-45). The function of this protein is unknown and no
identical protein has ever been reported as a stress protein. I
propose to examine the biosynthesis and regulation of HPM-45
through preparation of mono-specific, polyclonal antibodies and
subsequent analysis of the biogenesis of HPM-45 at transcriptional
and translational levels. The specificity of HPM-45 induction
following amino acid deprivation and the time course of its
biosynthesis will be characterized. Specific antibodies to HPM-45
will also allow for the screening of a lambda gtll rat liver
expression library. Once identified, a cDNA insert corresponding
to the HPM-45 gene will be sub-cloned for use as a molecular probe
for mRNA analysis. The detection and characterization of genetic
control of HPM-45 by amino acid deprivation will add valuable
insight into the cellular response to starvation and the
nutritional regulation of gene expression.