Required for the proteolytic cleavage of the transcription factor RIM101 in response to alkaline ambient pH. May act as a scaffold protein that recruits the calpain-like protease RIM13 via VPS32 to its substrate RIM101 (By similarity). Interacts with RIM101 by binding to its two YPX[LI] motifs. Belongs to the palA/RIM20 family.