# MEMBRANE EVENTS FOLLOWING HORMONE BINDING TO LH RECEPTOR

> **NIH NIH R01** · COLORADO STATE UNIVERSITY · 1994 · $100,185

## Abstract

Luteinizing hormone/chorionic gonadotropic (LH/CG) receptors on the
corpus luteum and on Leydig cells bind luteinizing hormone (LH) and human
chorionic gonadotropin (hCG) to regulate steroid synthesis and secretion
from these glands.  The goal of this project is to better understand the
role of LH/CG receptor structure in regulation of fertility and how
gonadotropins may modulate events in LH/CG receptor function including
G-protein interactions, receptor internalization and CAMP activation.
First, we will examine whether gonadotropin binding causes size changes
in functional LH receptor complexes using two laser optical methods for
measuring protein molecular motions, polarized fluorescence depletion and
fluorescence photobleaching recovery.  Single-cell fluorescence energy
transfer measurements will be used to assess receptor-receptor
aggregation on the membrane.  Second, the effect of LH/CG structure on
receptor molecular motions will be assessed using tissue-cultured cells
bearing LH/CG receptors with C-terminal truncations.  Ligand binding to
these truncated receptors results in increased CAMP activation and more
rapid internalization, perhaps due to more rapid LH/CG receptor lateral
diffusion in the plasma membrane.  Third, the effects of deglycosylated
hCG and native hCG on LH/CG receptor motions will be evaluated on rat
Leydig cells and on MA-10 cells.  Binding of deglycosylated hCG to the
LH/CG receptor slows receptor down-regulation and internalization,
effects that may result from slower receptor lateral diffusion and fewer
receptor interactions with proteins needed for internalization.  Finally,
the association of non-receptor proteins including G-protein subunits and
MHC class I antigen with LH/CG receptors will be explored by a
photoproximity labeling technique that permits identification and
isolation of proteins physically proximal to a known membrane site.
Colorado State University has an unusual confluence of expertise is
reproductive physiology and instrumental facilities for membrane
structural studies.  This situation provides us a unique opportunity to
study both LH receptor organization and how this organization modulates
receptor function.

## Key facts

- **NIH application ID:** 2198794
- **Project number:** 5R01HD023236-07
- **Recipient organization:** COLORADO STATE UNIVERSITY
- **SAM.gov UEI:** LT9CXX8L19G1
- **Principal Investigator:** Deborah A Roess
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 1994
- **Award amount:** $100,185
- **Award type:** 5
- **Project period:** 1987-07-01 → 1996-05-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/2198794

## Citation

> US National Institutes of Health, RePORTER application 2198794, MEMBRANE EVENTS FOLLOWING HORMONE BINDING TO LH RECEPTOR (5R01HD023236-07). Retrieved via MORVS 2026-10-25 from https://api.morvs.ai/grant/nih/2198794. Licensed CC0.

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