Transcription factor that acts as a positive regulator of nonrepressible acid phosphatase activity. Is a major regulator of responses to nitrogen and carbon starvation and is essential for the expression of genes involved in vegetative incompatibility (like pin-c, het-6, and tol). Vegetative incompatibility is a non-self-recognition system ubiquitous in filamentous fungi which results in programmed cell death (By similarity). Was originally thought to be a phosphatase.