# Protein-membrane interactions in regulated exocytosis

> **NIH NIH R35** · UNIVERSITY OF COLORADO · 2021 · $379,142

## Abstract

PROJECT SUMMARY
Regulated exocytosis – stimulus-dependent exocytic vesicle fusion – mediates a broad range of fundamental
biological processes including nutrient homeostasis, hormonal signaling, synaptic transmission, and elimination
of transformed or virally infected cells. Imbalances in these exocytic pathways lead to major forms of human
disease such as diabetes, neurological disorders, immunodeficiency, and cancer. The overall goal of this
research is to establish the molecular principles of regulate exocytosis, using the trafficking of the glucose
transporter GLUT4 as a model system. In our previous research, we delineated the molecular mechanisms of
known exocytic regulators in the GLUT4 pathway. In this research, we will focus on a group of new regulatory
factors identified in our recent genome-wide CRISPR screens investigating GLUT4 exocytosis. We will carry
out in-depth biochemical, biophysical, cell biological, and genetic studies to address two key questions: 1) How
do exocytic mediators act in concert to drive exocytic vesicle fusion? 2) How is exocytic vesicle fusion coupled
to other cellular processes to achieve an integrated response? To answer the first question, we will define the
molecular mechanisms by which SNARE-binding regulators, alone and in combination, control SNARE
zippering, membrane tethering, bilayer curvature generation, lipid mixing, and content mixing. To answer the
second question, we will determine whether and how the GLUT4 exocytic pathway is influenced by stimulus-
dependent phosphorylations on SNAREs, conserved SM proteins, specialized exocytic regulators, and
mediators of clathrin-mediated endocytosis. We will also investigate the functional roles and molecular basis of
cargo retrieval in establishing an integrated exocytic response. Besides these mechanistic analyses, we will
continue to identify, validate and characterize new trafficking regulators based on the candidate genes from our
unbiased and targeted CRISPR screens. The mechanistic studies and CRISPR screens are fully
complementary and will provide a comprehensive understanding of exocytosis regulation that neither approach
alone could generate. Successful completion of this proposed research will fill major gaps in the knowledge of
regulated exocytosis and will serve as a springboard for understanding the general principles of membrane
trafficking. Ultimately, insights gleaned from this work will facilitate the development of new therapeutic
strategies for diseases caused by dysregulated exocytosis.

## Key facts

- **NIH application ID:** 10136004
- **Project number:** 5R35GM126960-04
- **Recipient organization:** UNIVERSITY OF COLORADO
- **Principal Investigator:** Jingshi Shen
- **Activity code:** R35 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $379,142
- **Award type:** 5
- **Project period:** 2018-04-01 → 2023-03-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10136004

## Citation

> US National Institutes of Health, RePORTER application 10136004, Protein-membrane interactions in regulated exocytosis (5R35GM126960-04). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/10136004. Licensed CC0.

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