WAVE forms hetero- and homo-oligomeric complexes at integrin junctions in Drosophila visualized by bimolecular...

Area of Science:

• Cell Biology
• Developmental Biology
• Molecular Biology

Background:

• Actin polymerization is crucial for cell shape and tissue development.
• WASP/WAVE proteins are key regulators of actin nucleation via the Arp2/3 complex.
• The WAVE complex is a conserved pentameric heterocomplex regulating WAVE protein function.

Purpose of the Study:

• To visualize the subcellular localization and dynamics of the WAVE complex in living Drosophila.
• To investigate the molecular interactions within the WAVE complex, including WAVE-Abi and WAVE-WAVE interactions.
• To determine the role of WAVE complexes in actin polymerization and cell adhesion.

Main Methods:

• Established Bimolecular Fluorescence Complementation (BiFC) in Drosophila to visualize protein complex formation in vivo.
• Utilized split-YFP combinations for real-time imaging of WAVE complex assembly.
• Employed RNA interference (RNAi) to suppress components of the WAVE and Arp2/3 complexes.

Main Results:

• Visualized WAVE-Abi complex formation and WAVE homodimerization in living flies.
• Identified the N-terminal WAVE homology domain (WHD) as critical for WAVE-Abi and WAVE-WAVE interactions.
• Demonstrated that WAVE complexes localize to basal cell compartments and co-localize with Integrin and Talin.
• Showed that WAVE-dependent Arp2/3-mediated actin nucleation is vital for stable integrin junctions.

Conclusions:

• The WAVE complex undergoes dynamic assembly and oligomerization in vivo.
• WAVE complex formation at basal cell compartments is essential for actin polymerization and integrin-mediated cell adhesion.
• WAVE proteins play a critical role in maintaining tissue integrity during development.