Regulation of the Intracellular Trafficking of Ajuba by Cell Density and Cell Cycle-Dependent Mechanisms

<p>The intracellular localization of Ajuba, a LIM domain-containing protein, holds essential value for various cellular activities. Previous studies from the laboratory have implicated Ajuba as a repressor of ATR in human cells. This study focused on unveiling the intricate mechanisms governing Ajuba's localization dynamics through studies of its intracellular trafficking under cell cycle-dependent changes, and responses to cell density. Through targeted deletion experiments, it was found that Ajuba's LIM domain plays an essential role in its nuclear localization, while a nuclear export signal (NES) in its preLIM domain guides its exit from the nucleus to the cytoplasm. The essential role of the NES signal was underlined by insights into Ajuba variant 1 and its response to Leptomycin B treatment. Specific GFP fusion experiments provided additional evidence for the active nuclear import mediated by the LIM domain. Ajuba's expression levels significantly increased during mitosis, and this surge declined upon mitotic exit, independent of protease-mediated degradation. Additionally, a correlation between cell density and Ajuba's cellular localization was established, with highly dense cells displaying diverse distribution patterns across cell lines. Notably, Leptomycin B treatment led to significant alterations in Ajuba's cellular localization response to cell density. These findings highlight the intricate relationship between Ajuba, cell density, and cell cycle. These findings underscore the complex interplay between Ajuba's cellular localization, cell cycle progression, and cell density. This study contributes to a deeper understanding of the molecular mechanisms fundamental to Ajuba's dynamic cellular distribution, shedding light on its potential implications in cell growth.</p>

Name thesis:degree_name

Doctor of Philosophy

Level thesis:degree_level

Doctoral

Discipline thesis:degree_discipline

Biology

Grantor

The Graduate School and University Center of The City University of New York

Year dc:date.available

2024

Author dc:creator

• Sun, Huanhuan

Advisor dc:contributor.advisor

• Diego Loayza

Committee members dc:contributor.committeemember

• Hualin Zhong
• David Foster
• Patricia Cortes
• Nadya Dimitrova

• Biology

Repository record dc:identifier

https://academicworks.cuny.edu/gc_etds/5631

OAI identifier oai:identifier

oai:academicworks.cuny.edu:gc_etds-6735