Structure of yeast RAVE bound to a partial V₁ complex.

Area of Science:

• Cellular Biology
• Biochemistry
• Structural Biology

Background:

• Vacuolar-type ATPases (V-ATPases) are crucial proton pumps for intracellular acidification in eukaryotes.
• V-ATPases comprise soluble V1 and membrane-bound VO subcomplexes that reversibly dissociate to regulate activity.
• The RAVE complex is essential for V1-VO reassembly, facilitating V-ATPase function.

Purpose of the Study:

• To elucidate the structural basis of RAVE-mediated V1-VO reassembly.
• To determine the interaction interface between yeast RAVE and the V1 subcomplex.
• To understand how RAVE binding influences V1 conformation for VO association.

Main Methods:

• Electron cryomicroscopy (cryo-EM) was employed to visualize the yeast RAVE-V1 complex.
• Structural analysis focused on the L-shaped RAVE complex and its interaction with V1 subunits.
• Comparative analysis with ATP synthase structures identified unique binding regions.

Main Results:

• The cryo-EM structure revealed an L-shaped RAVE complex with specific subunit orientations (Rav2p towards membrane, Skp1p distant).
• Only Rav1p directly interacts with V1, binding to a unique region on subunit A not present in ATP synthases.
• The V1 complex, though partially dissociated (missing subunits), adopts a conformation conducive to VO binding.

Conclusions:

• RAVE acts as a scaffold, positioning V1 for efficient reassembly with VO.
• The interaction interface and conformational changes induced by RAVE are key to regulating V-ATPase proton pumping activity.
• This structural insight provides a foundation for understanding V-ATPase regulation and potential therapeutic targeting.