# MONOCLONAL ANTIBODIES AS PROBES TO VITAMIN D3 ACTION

> **NIH NIH R01** · BAYLOR COLLEGE OF MEDICINE · 1987 · $167,583

## Abstract

The diverse biologic actions of 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) are
thought to be mediated byintracellular receptor proteins which appear to
operate at the level of the cell nucleus.  We propose to continue our study
of these unique polypeptides derived from both avian and mammalian sources
utilizing immunologic as well as conventional probes.  Investigation will
focus upon four areas essential to our understanding of the molecular
mechanism of 1,25(OH)2D3 action:  1) physical and biochemical properties of
receptors, 2) intracellular biology of receptors and the role of
1,25(OH)2D3 3) functional characterization of receptors, and 4) molecular
defects in receptors which confer cellular resistance to 1,25(OH)2D3.
Physical and biochemical characterization will include evaluation of the
two antigenically related forms of the avian receptor, topological mapping
of both avian and mammalian receptors, determination of mammalian
1,25(OH)2D3-dependent receptor phosphoamino acid species, and isolation and
sequence analysis of both avian and mammalian receptors.  Aspects of the
biology of 1,25(OH)2D3 receptors will include further evaluation of the
intracellular origins of unoccupied forms, receptor synthesis and
degradation, the effects of 1,25(OH)2D3 on cellualr levels of receptor and
its mRNA, the nature and mechanism of receptor inactivation.  Functional
studies will include determination of potential receptor enzymatic
activities, evaluation of teh functional significance of receptor
modification, and analysis of receptor DNA sequence preference utilizing
cloned vitamin D-dependent calbindin gene and receptor gene fragments.
Evaluation of molecular abnormalities will involve the application of the
above technology to the examination of abberrant human receptors from
fibroblasts obtained from patients with reisitance to 1,25(OH)2D3 as well
as from developed nonhuman variants.  Collectively, the studies proposed
here on normal receptors represent an integrated approach to the
elucidation of the role of receptor in mediating various bilogical
phenomena regulated by 1,25(OH)2D3.  In addtion, they provide the basis for
interpreting molecular defects in receptors which may be associated with
vitamin D3-resistant disease states.

## Key facts

- **NIH application ID:** 3158445
- **Project number:** 5R01AR038170-02
- **Recipient organization:** BAYLOR COLLEGE OF MEDICINE
- **SAM.gov UEI:** FXKMA43NTV21
- **Principal Investigator:** J WESLEY PIKE
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 1987
- **Award amount:** $167,583
- **Award type:** 5
- **Project period:** 1986-04-01 → 1991-03-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/3158445

## Citation

> US National Institutes of Health, RePORTER application 3158445, MONOCLONAL ANTIBODIES AS PROBES TO VITAMIN D3 ACTION (5R01AR038170-02). Retrieved via MORVS 2026-10-24 from https://api.morvs.ai/grant/nih/3158445. Licensed CC0.

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