# Src-mediated pathways regulating adherens junction assembly.

> **NIH NIH R01** · UNIVERSITY OF ILLINOIS AT CHICAGO · 2020 · $313,804

## Abstract

Project Summary
Endothelial barrier is regulated at the level of adherens junctions (AJs), cell-cell adhesion structures mediated
by the transmembrane protein VE-cadherin. Current model suggests that the tyrosine kinase c-Src functions as
a negative regulator of endothelial barrier stimulating disassembly of AJs through phosphorylation of VE
cadherin. However, our studies challenge this paradigm. We found that direct activation of Src using our
engineered probe transiently enhances barrier function and induces formation of morphologically distinct AJs
that exhibit reduced permeability. Our preliminary evidence suggests that Src-induced enhancement of
endothelial barrier is mediated through signaling pathway regulating small GTPase Arf6. We also found that
phosphorylation of VE cadherin on Tyr658/Tyr731 is critical for barrier strengthening by Src. Our studies also
show that Src promotes formation of new contacts with extracellular matrix (focal adhesions) and stimulates
interaction of focal adhesion protein p130Cas with VE cadherin. Based on these novel findings we hypothesize
that Src signaling though Arf6 and VE-cadherin, and stimulation of new focal adhesions promote formation of
AJs leading to strengthening of endothelial barrier. To define the role of each pathway downstream of Src, we
propose to address the following questions. 1) We will determine the role of Arf6 activity in Src-stimulated
formation of AJs, and identify Src-mediated pathways that activate Arf6. 2) We will define the role of Src
signaling in AJs and the role of individual phosphorylation sites on VE-cadherin in formation of new AJs and
enhancement of endothelial permeability. 3) We will determine the role of focal adhesions in Src-mediated
enhancement of endothelial barrier and define the role of Src signaling through specific focal adhesion
proteins. The timing and location of Src-mediated signaling is critical for regulation of AJs. Thus, to achieve
precise temporal and spatial control of Src-mediated processes regulating AJs, we propose to employ
engineered protein tools that will allow us to regulate precisely the activity of Src and phosphorylation of VE-
cadherin in living cells. The level of control is unprecedented in that Src can be selectively activated and
inactivated with tight temporal control and in specific subcellular locations in living cells. Importantly, Src
activation can be restricted to a specific downstream targets and subcellular locations. Using these tools, we
will dissect individual Src-mediated signaling pathways controlling assembly of AJs.

## Key facts

- **NIH application ID:** 9932380
- **Project number:** 5R01GM118582-04
- **Recipient organization:** UNIVERSITY OF ILLINOIS AT CHICAGO
- **Principal Investigator:** ANDREI V KARGINOV
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $313,804
- **Award type:** 5
- **Project period:** 2017-09-01 → 2022-05-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9932380

## Citation

> US National Institutes of Health, RePORTER application 9932380, Src-mediated pathways regulating adherens junction assembly. (5R01GM118582-04). Retrieved via AI Analytics 2026-05-22 from https://api.ai-analytics.org/grant/nih/9932380. Licensed CC0.

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