# MODIFICATION OF EGG PLASMA MEMBRANE

> **NIH NIH R01** · UNIVERSITY OF KANSAS MEDICAL CENTER · 1994 · $124,818

## Abstract

The long term objective of this proposal is to identify the
biochemical steps which act to transduce the initial stimulus of
sperm-egg fusion into a signal to begin cell division.  It is now well
established that fertilization, like many other mitogenic events,
involves activation of a tyrosine protein kinase and it has recently been
shown that this results in phosphorylation, on tyrosine, of a high
molecular weight egg cortex protein (HMWCP).  This phosphorylation event
is regulated by a fertilization-induced alkaline shift in pH, and occurs
during the 'pH critical' stage of egg activation in which this alkaline
shift is essential for successful induction of cell division.  It is
proposed that HMWCP phosphorylation acts as a pH sensitive transducer
that responds to a relatively small change in pH, and, in turn, activates
components of the cell cycle control which themselves are not sensitive
to small changes in pH.  This represents a novel signal transduction
mechanism which amy function in a variety of other systems in which
mitogenic stimuli induce an alkaline shift in cytoplasmic pH.
          The first specific aim of this proposal is to characterize the
HMWCP immunohistochemically and biochemically in order to determine its
subcellular location, relative phosphorylation state, and number of
phosphorylation sites.  Further biochemical analysis together with
microinjection experiments will be done to examine the function of this
protein and test the hypothesis that phosphorylation of the HMWCP plays a
key role in egg activation.  Specific attention will be paid to the
possibility that HMWCP phosphorylation plays a role in triggering the
cyclin/MPF pathway leading to initiation of mitosis.  The second aim will
be to characterize the tyrosine kinase which phosphorylates the HMWCP and
use an in vitro system to examine the mechanism for its sensitive
regulation by pH.

## Key facts

- **NIH application ID:** 2197134
- **Project number:** 5R01HD014846-14
- **Recipient organization:** UNIVERSITY OF KANSAS MEDICAL CENTER
- **SAM.gov UEI:** YXJGGNC5J269
- **Principal Investigator:** William H. Kinsey
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 1994
- **Award amount:** $124,818
- **Award type:** 5
- **Project period:** 1991-08-01 → 1996-04-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/2197134

## Citation

> US National Institutes of Health, RePORTER application 2197134, MODIFICATION OF EGG PLASMA MEMBRANE (5R01HD014846-14). Retrieved via MORVS 2026-10-25 from https://api.morvs.ai/grant/nih/2197134. Licensed CC0.

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