Mating type proteins are sequence specific DNA-binding proteins that act as master switches in yeast differentiation by controlling gene expression in a cell type-specific fashion. In P.angusta, all mating-type proteins (MATA1, MATALPHA1 and MATALPHA2) are encoded on one idiomorph, consistent with the fact that P.angusta is a homothallic haploid in which any strain can mate with any other strain. Belongs to the MATALPHA1 family.