The RhoGEF protein Plekhg5 self-associates via its PH domain to regulate apical cell constriction

Area of Science:

• Cell Biology
• Developmental Biology
• Molecular Biology

Background:

• Rho guanine nucleotide exchange factors (RhoGEFs) regulate essential cellular processes.
• The RhoGEF gene plekhg5 is known to control apical constriction in Xenopus gastrulation.
• The precise molecular mechanism of plekhg5 function remains incompletely understood.

Purpose of the Study:

• To elucidate the detailed mechanism of Plekhg5 action during Xenopus gastrulation.
• To investigate the roles of N-terminal and C-terminal sequences in Plekhg5 localization.
• To determine the importance of Plekhg5 self-association and its PH domain in regulating apical constriction.

Main Methods:

• Analyzing Plekhg5 localization using its N-terminal and C-terminal sequences.
• Investigating Plekhg5 self-association via its PH domain.
• Assessing the functional rescue of Plekhg5 mutants lacking specific domains or activity.
• Introducing a point mutation in the PH domain associated with human disease.

Main Results:

• Plekhg5 apical cortical localization requires N-terminal sequences and guanine nucleotide exchange activity.
• C-terminal sequences of Plekhg5 prevent basolateral mislocalization.
• Plekhg5 self-associates through its PH domain, rescuing mutant functions.
• A disease-associated PH domain mutation disrupts self-association and impairs apical constriction.

Conclusions:

• Both PH-mediated self-association and N-terminal domain-mediated localization are critical for Plekhg5 function.
• Proper subcellular localization and self-association are essential for Plekhg5's role in apical constriction during gastrulation.
• Understanding Plekhg5 mechanisms provides insights into developmental processes and human disease variants.