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. Transcriptional activator that induces the transcription of alpha-specific mating genes. Induced by HBR1 in response to hemoglobin and growth signals. The C.albicans mating-type-like (MTL) locus contains, in addition to the genes for the regulatory proteins (MTLA1, MTLA2, MTLALPHA1 and MTLALPHA2), a and alpha idiomorphs of a phosphatidylinositol kinase (PIKA and PIKALPHA), a poly(A) polymerase (PAPA and PAPALPHA) and an oxysterol binding protein-like protein (OBPA and OBPALPHA). MTLALPHA1 is not represented in the genomic sequence of strain SC5314 because that haploid assembly includes the mating type a allele of this locus. Most C.albicans strains are heterozygous at the MTL locus and do not readily undergo white-opaque switching and mating, but mating occurs in hemi- or homozygous strains. Mating takes place in opaque cells, produces tetraploid progeny and seems to occur rarely, if at all, in nature. Conservation of mating capacity is rather thought to be due to the simultaneously regulated white-opaque switch, which seems to play an important role in host commensalism. Belongs to the MATALPHA1 family.