# ASSAYS FOR AND MECHANISMS OF ACTION OF TUMOR PROMOTERS

> **NIH NIH R01** · UNIVERSITY OF HAWAII AT MANOA · 1990 · $166,418

## Abstract

Signal transduction mechanisms are menas by which cells relay
information from the cellular exterior to the cellular interior.
The definition of these various mechanisms is important in
understanding cellular proliferation, tumor promotion and
neoplastic development.  A major signal transduction mechanism
recently brought to view is that of phosphatidylinositol turnover
with the production of the protein kinase C activating
diacylglycerol and the Ca2+ mobilizing inositol-1,4,5-
trisphosphate.  The present research further defines this signal
transduction mechanism and focuses on its role in protein
phosphorylation, protein dephosphorylation, Ca2+ release, cell
proliferation and tumor promotion.

We have identified a protein phosphatase whose activity is
stimulated by inositol-1,4,5-trisphosphate.  As well, we have
identified a phosphoprotein substrate, p37, of protein kinase C that
depends on extracellular Ca2+ for translocaiton from the soluble
to particulate fraction on stimulation by TPA or serum and have
identified p37 as lipocortin.  Our short-term goals are to:  1)
characterized the inositol-1,4,5-trisphosphate stimulated protein
phosphatase; 2) make antibodies to the phosphatase; 3) determine
if the phosphatase plays a role in Ca2+ release, Ca2+-dependent
cell cycle progression, and tumor promoter action; 4) clone the
gene of the protein phosphatase and determine its amino acid
sequence; and 5) determine if specific substrates of the inositol-
1,4,5-trisphosphate protein phosphatase and of protein kinase A
and C are correlated with Ca2+-dependent cell cycle transitions.

It is through a basic understanding of the cell biology and
biochemistry of cell proliferation that will allow us to rationally
design methods to prevent, interrupt and treat neoplastic disease.

## Key facts

- **NIH application ID:** 3179137
- **Project number:** 5R01CA039745-06
- **Recipient organization:** UNIVERSITY OF HAWAII AT MANOA
- **SAM.gov UEI:** NSCKLFSSABF2
- **Principal Investigator:** ALTON L BOYNTON
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 1990
- **Award amount:** $166,418
- **Award type:** 5
- **Project period:** 1985-08-01 → 1991-07-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/3179137

## Citation

> US National Institutes of Health, RePORTER application 3179137, ASSAYS FOR AND MECHANISMS OF ACTION OF TUMOR PROMOTERS (5R01CA039745-06). Retrieved via MORVS 2026-10-25 from https://api.morvs.ai/grant/nih/3179137. Licensed CC0.

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