RAP-1 and the RAL-1/exocyst pathway coordinate hypodermal cell organization in Caenorhabditis elegans.

Area of Science:

• Cell Biology
• Genetics
• Developmental Biology

Background:

• Rap1 GTPase regulates integrin activation and cell-cell contacts.
• Rap1 null mutants in C. elegans are viable and fertile.
• The exocyst complex is involved in vesicle trafficking and cell polarity.

Purpose of the Study:

• To identify genes essential for viability in C. elegans rap-1 mutants.
• To elucidate the function of the Ral-1/exocyst pathway in development.
• To investigate the genetic interactions between Rap1 and Ral-1 pathways.

Main Methods:

• Synthetic lethal RNAi screen in C. elegans rap-1 mutants.
• Depletion of exocyst components (exoc-8, sec-5) via RNAi.
• Analysis of embryonic development and larval stages.
• Genetic interaction studies.

Main Results:

• Ral-1, exoc-8, and sec-5 are specifically required for the viability of rap-1 mutants.
• The Ral-1/exocyst pathway coordinates hypodermal cell movement and elongation during embryonic development.
• Rap1 and Ral-1/exocyst pathways target alpha-catenin homologue HMP-1 to the lateral membrane.
• These pathways function in parallel during larval stages.

Conclusions:

• The exocyst complex acts as a downstream effector of Ral-1 in vivo.
• The Rap1 and Ral-1/exocyst pathways cooperate in cell migration and developmental processes.
• Provides in vivo evidence for the exocyst complex's role in Ral-1-mediated cell migration.