Transcription co-regulator that might be involved in the regulation of the expression of the gene cluster that mediates the biosynthesis of calbistrins and related compounds such as decumbenones. Calbistrin A is a secondary metabolite with an interesting structure that was recently found to have bioactivity against leukemia cells. It consists of two polyketides linked by an ester bond: a bicyclic decalin containing polyketide and a linear 12 carbon dioic acid structure. Expression is induced in complex medium (Czapek yeast autolysate medium) supporting calbistrin production. Calbistrin A has been reported to possess a number of interesting bioactivities including antifungal active against Candida albicans and cytotoxic toward both healthy and leukemic human cells.