Transcription factor that mediates regulation of both acid- and alkaline-expressed genes in response to ambient pH. At alkaline ambient pH, activates transcription of alkaline-expressed genes (including RIM101 itself) and represses transcription of acid-expressed genes. Specifically recognizes and binds the consensus sequence 5'-CCAAGAA-3'. Required for the control of alkaline pH-induced filamentation (dimorphic switch) and virulence. Binds to DNA. Interacts with RIM20, which binds to the YPX[LI] motifs and is required for proteolytic processing (By similarity). By alkaline conditions. Activated by C-terminal proteolytic cleavage. At neutral to alkaline ambient pH, the signaling protease (probably RIM13) cleaves RIM101 to yield the 74 kDa functional form. Also exists as a 65 kDa form at acidic pH, which may govern pH-independent processes. Belongs to the pacC/RIM101 family.