# MECHANISMS OF NUCLEOSIDE TRANSPORT IN MAMMALIAN CELLS

> **NIH NIH R01** · ST. JUDE CHILDREN'S RESEARCH HOSPITAL · 1989 · $166,885

## Abstract

Our previous studies have demonstrated that mammalian cells
have two distinct types of nucleoside transport that differ by
1000-fold in their sensitivity to the inhibitor
nitrobenzylthionosine, and have defined the transport properties
of model cell lines having one or the other (S49 mouse lymphoma
and Walker 256 rat carcinosarcoma, respectively), or both (L1210
mouse leukemia) of these activities.  The continuation of this
project will focus on the purification of the proteins mediating
NBMPR-sensitive and -resistant nucleoside transport, and
comparison of the structural and functional properties of those
proteins.  Monoclonal antibodies will be obtained to use as
specific probes of the transport proteins and to aid in their
purification affinity chromatography utilizing NBMPR and
adenosine as ligands will also be employed in the purification
studies.  The biological activity of the proteins will be monitored
during purification by reconstitution of transport activity in lipid
vesicles.  Reconstitution will also be used to compare the
functional properties of the purified proteins.  The structures of
the proteins will be compared by peptide mapping, and sequencing
of the peptides bearing the substrate and NBMPR binding sites.
The information gained in the study of the purified transport
proteins will also be used to examine the structure and orientation
of the proteins as they exist in their native state in the
membranes of S49 and Walker 256 cells.  The relationship between
NBMPR-sensitive and - resistant transport will be examined in
L1210 cells.  These studies will use genetic and biochemical
approaches to determine whether the two transport activities are
properties of two separate and distinct proteins or two related
forms of the same protein.  The transport protein(s) of a cell line
that exhibits anomolous NBMPR-binding properties will also be
examined to gain a better understanding of the relationship
between inhibitor binding sites and substrate permeation sites.  It
is expected that the information gained form these studies will
contribute significantly to the long range goals of understanding
the physiological roles of nucleoside transport in mammalian
cells, and in designing approaches to using transport inhibitors to
increase the selectivity of antimetabolites used in cancer
chemotherapy.

## Key facts

- **NIH application ID:** 3171268
- **Project number:** 5R01CA033362-06
- **Recipient organization:** ST. JUDE CHILDREN'S RESEARCH HOSPITAL
- **SAM.gov UEI:** JL4JHE9SDRR3
- **Principal Investigator:** JUDITH A. BELT
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 1989
- **Award amount:** $166,885
- **Award type:** 5
- **Project period:** 1983-05-01 → 1990-11-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/3171268

## Citation

> US National Institutes of Health, RePORTER application 3171268, MECHANISMS OF NUCLEOSIDE TRANSPORT IN MAMMALIAN CELLS (5R01CA033362-06). Retrieved via MORVS 2026-10-25 from https://api.morvs.ai/grant/nih/3171268. Licensed CC0.

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