# Defining the molecular mechanisms underlying apical-basal polarity establishment and morphogenesis

> **NIH NIH F31** · UNIV OF NORTH CAROLINA CHAPEL HILL · 2020 · $35,666

## Abstract

Abstract
Most tissues in our bodies and those of other animals are epithelia. Proper tissue architecture and integrity
require apical-basal polarity establishment and maintenance, cell-cell and cell-matrix adhesion, and linkage of
adhesions to the actin cytoskeleton. These also mediate force generation, allowing cells to change shape and
move. Most cancers are of epithelial origin, and in many different cancers mutation or altered expression of
polarity and junctional proteins leads to changes in cell polarity, promoting cell migration and cell invasion.
Linkage of cadherin-based cell-cell adherens junction (AJs) with the actin cytoskeleton regulate dynamic cell
behaviors during development and in cancer. A critical player integrating tissue adhesion and polarity in both
mammals and Drosophila is Afadin/Canoe (Cno). Cno is a multidomain protein that in Drosophila plays key
roles in processes ranging from apical-basal polarity establishment to maintaining AJ-cytoskeleton linkage
during mesoderm invagination, germ-band extension, and collective cell migration during dorsal closure. Here I
address two outstanding questions in the field: by what mechanisms does Cno work to control tissue
architecture and dynamic cell behaviors, and how do upstream inputs regulate Cno's function? I do so via two
Aims: 1) Define mechanisms underlying Cno's ability to link the AJs with the actin cytoskeleton during
morphogenesis, and 2) Define how Dizzy, a Rap1 activity regulator, coordinates Cno localization and function
during embryonic development, and determine where active Rap1 localizes. My hypothesis in Aim 1 is that
Cno's PDZ and F-actin binding (FAB) domains play key roles in Cno's localization and function at many stages
but may not be essential for all roles. Using CRISPR/Cas9, I engineered cno's locus to reintroduce a series of
mutants of Cno's PDZ and FAB domains, to define how they contribute to Cno localization and function
throughout development, thus providing insights into Afadin's roles in mammals. In parallel I will perform
protein-protein interaction analysis of Cno mutant proteins in vitro and in vivo. Aim 2 is built on the hypothesis
that an active pool of Rap1 regulates Cno activity, and that Dizzy is the predominant Rap1 GEF regulating
Cno's localization and thus function during embryogenesis. To test this, I will explore how Rap1, an upstream
regulator of Cno, coordinates Cno localization and function. I will compare the phenotype of Cno knockdown
with that of Rap1, and with Dizzy and RapGAP1 knockdown, known regulators of Rap1 activity. In parallel I will
develop tools revealing where active Rap1 localizes. This study will define how Rap1 activity regulators, Rap1,
and Cno work to regulate dynamic cell behaviors and will provide critical information to understand their roles
in disease. Through this training, I will gain cutting edge skills in molecular biology, biochemistry, genetics and
microscopy, learn to bridge protein structure with doma...

## Key facts

- **NIH application ID:** 9978570
- **Project number:** 5F31GM131521-02
- **Recipient organization:** UNIV OF NORTH CAROLINA CHAPEL HILL
- **Principal Investigator:** Kia Zolee Perez-Vale
- **Activity code:** F31 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $35,666
- **Award type:** 5
- **Project period:** 2019-08-01 → 2021-07-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9978570

## Citation

> US National Institutes of Health, RePORTER application 9978570, Defining the molecular mechanisms underlying apical-basal polarity establishment and morphogenesis (5F31GM131521-02). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/9978570. Licensed CC0.

---

*[NIH grants dataset](/datasets/nih-grants) · CC0 1.0*