Transcription factor that regulates the expression of the gene cluster that mediates the biosynthesis of the isoquinoline alkaloids fumisoquin A, fumisoquin B and fumisoquin C; as well as small amounts of fumipyrrole as a shunt metabolite (PubMed:25582336, PubMed:27065235). The products of the cluster lead to a brown coloration and are important for growth and conidiation (PubMed:25582336). Expression is induced by the cAMP-dependent protein kinase A signaling pathway (PubMed:25582336). Leads to reduced growth and sporulation, but does not affect virulence in infected mice (PubMed:25582336). Impairs the production of isoquinolines (PubMed:27065235).