# MECHANISM OF ACTION OF A HUMAN GRANULOPOIETIN

> **NIH NIH R01** · UNIVERSITY OF CALIFORNIA LOS ANGELES · 1987 · $167,446

## Abstract

Colony-stimulating factors (CSFs) are required for in vitro growth of
myeloid colonies in semi-solid systems.  There is considerable clinical
evidence to suggest that these glycoprotein mediators are the physiological
regulators of human granulopoiesis.  Little is known about the molecular
characteristics and mechanism of action of human CSFs because purified
protein has not been available.  Recently we have purified human
granulocyte-macrophage CSF (GM-CSF) and obtained cDNA clones which are
efficiently expressed in COS monkey cells.  With the availability of these
reagents it is now possible to investigate the physiological functions of
this important hematopoietic regulator.

Based on the fact that GM-CSF is active in the picomolar range, it is
likely to exert its effects through binding to a specific receptor.
Recombinant (biosynthetic) GM-CSF will be used to study specific binding to
responsive target cells that have been identified in biological assays.
The specific binding assay will also be used to identify the target cells
in normal human bone marrow and peripheral blood, as well as the presence
of high affinity binding sites on cells isolated from patients with various
myeloproliferative disorders.  The molecular weight and subunit structure
of the GM-CSF receptor will be characterized by affinity labeling.  The
receptor will be purified from a human cell line which is found in the
specific binding assay to have a high number of receptors.  Membranes will
be prepared and the proteins solubilized and fractionated on a
GM-CSF-affinity column.  Proteins bound to the column will be eluted with
salt and further fractionated by gel filtration.  Purification will be
monitored by binding of 125I-GM-CSF and SDS polyacrylamide gel
electrophoresis.  Amino acid sequence from the N-terminus of the purified
receptor will be used to construct oligonucleotide probes.  A cDNA library
prepared from mRNA enriched for sequences contained in cells which express
the GM-CSF receptor will be screened with the oligonucleotide probes.
Positive clones will be verified by Northern analysis and DNA sequencing.

Studies will be initiated to examine the events following binding of GM-CSF
to the receptor such as receptor internalization, kinase activities, and
possible second messengers.  Ultimately, genetic variants resistant to
GM-CSF action will be used to establish the role of specific pathways in
GM-CSF action.  (J)

## Key facts

- **NIH application ID:** 3179756
- **Project number:** 5R01CA040163-03
- **Recipient organization:** UNIVERSITY OF CALIFORNIA LOS ANGELES
- **SAM.gov UEI:** RN64EPNH8JC6
- **Principal Investigator:** JUDITH Cheryl GASSON
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 1987
- **Award amount:** $167,446
- **Award type:** 5
- **Project period:** 1985-07-01 → 1988-06-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/3179756

## Citation

> US National Institutes of Health, RePORTER application 3179756, MECHANISM OF ACTION OF A HUMAN GRANULOPOIETIN (5R01CA040163-03). Retrieved via MORVS 2026-10-25 from https://api.morvs.ai/grant/nih/3179756. Licensed CC0.

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