# Structure and assembly of membrane proteins at tight junctions

> **NIH NIH R35** · STATE UNIVERSITY OF NEW YORK AT BUFFALO · 2024 · $159,785

## Abstract

Project Summary
Tight junctions (TJs) at the boundaries of endothelial and epithelial cells are critical in the development and
function of vertebrates because they enable these tissues to separate, protect, and shape external epidermis
and limbs and internal organs and glands. TJs regulate molecular transport through the spaces between
individual cells (paracellular) while adhering cellular sheets. TJs perform two vital functions in tissues: 1) form
barriers to restrict paracellular flux of small molecules, protecting organisms from the external environment and
separating internal body compartments; and 2) creating size- and charge-selective pores, allowing permeability
of ions that maintain electrochemical gradients. Numerous proteins amass at TJs to form the macromolecular
assemblies necessary for barrier and pore function. But two families of membrane proteins—claudins and
TAMPs (TJ-associated Marvel proteins)—predominate TJ assembly, architecture, and function. As these TJ
integral membrane proteins (TJIMPs) are the sole components to span intracellular, intramembraneous, and
extracellular space, they act as cytoskeletal scaffolds and assemble side-by-side within a membrane (cis) and
with TJIMPs from adjacent cell membranes (trans) to form barriers and pores. The molecular structure of TJs
is dynamic. Changes in protein composition, interaction, conformation, or modification—useful for assembling
TJs to precisely tune paracellular transport under normal conditions—can also be mis-assembled, resulting in
pathologies such as cancer, Alzheimer’s, Parkinson’s, Huntington’s, ALS, stroke, food poisoning and
inflammatory bowel disease, renal wasting, hepatitis, and diseases of the skin, eyes, and ears. Molecular level
insights into TJ structure and dynamics; the mechanisms of assembly that govern barrier and pore function;
and how disabling these mechanisms leads to pathologies, remain unresolved matters in our fundamental
understanding of TJs. We propose here a comprehensive research program that uses highly interdisciplinary
approaches to determine structure–interaction–function relationships between TJIMPs at dynamic TJ
microenvironments. These approaches integrate structural biology of TJIMPs and their complexes with
information obtained by traditional and state-of-the-art bioinformatics, biochemical, biophysical, and functional
experiments. The research program intends to resolve the underlying molecular principles of TJ assembly and
disassembly by confronting technical challenges and, in the near-term, by answering specific questions on
TJIMP interaction networks, the basis of gut barrier breakdown by a bacterial toxin, and the mechanisms of
TJIMP form and function at the blood-brain barrier. The long-term goal of our laboratory is to elucidate the
molecular bases for construction, destruction, and reconstruction of TJs, occurring both naturally or via
disease-causing mechanisms, and to use the achieved insights to advance design and developm...

## Key facts

- **NIH application ID:** 11034616
- **Project number:** 3R35GM138368-04S1
- **Recipient organization:** STATE UNIVERSITY OF NEW YORK AT BUFFALO
- **Principal Investigator:** Alex J. Vecchio
- **Activity code:** R35 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $159,785
- **Award type:** 3
- **Project period:** 2020-08-01 → 2025-07-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/11034616

## Citation

> US National Institutes of Health, RePORTER application 11034616, Structure and assembly of membrane proteins at tight junctions (3R35GM138368-04S1). Retrieved via AI Analytics 2026-05-22 from https://api.ai-analytics.org/grant/nih/11034616. Licensed CC0.

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