GGPS1 is PART of the prenyltransferase family. GGPS1 is widely expressed in testis, heart and skeletal muscle, GGPS1 is localized in the cytoplasm and catalyzes the formation of geranylgeranyl pyrophosphate, a precursor of geranylgeranylated proteins and carotenoids. GGPS1 is a significant enzyme that is responsible for the C20-prenylation of proteins and for the regulation of a nuclear hormone receptor.