The Function of Geranylgeraniol

Abstract

Geranylgeraniol is a natural isoprenoid derived from the mevalonate pathway and deoxyxylulose-phosphate pathway. This non-sterol isoprenoid is converted into geranylgeranyl diphosphate in animal cells and is then used as a substrate for protein prenylation by prenyltransferases and for the synthesis of menaquinone-4 from menadione by UbiA prenyltransferase domain-containing protein 1 (UBIAD1) prenyltransferase. More than 300 prenylated proteins have been identified in humans, which are involved in cell signaling during cell growth, differentiation, cytoskeletal function, and vesicle transport. Furthermore, GGOH also has protein prenylation-independent functions. In this review, we have summarized current information regarding GGOH, including the regulation of 3-hydroxy-3-methylglutaryl-coenzyme A reductase—which is the rate-limiting enzyme in the mevalonate pathway—modulation of brain function in ageing, suppression of inflammation, and enhancement of steroidogenesis in human and mammalian cells.