Regulation of HMG-CoA reductase activity in plants.

This brief review summarizes the current literature on the regulation of HMG-CoA reductase (HMGR) in plants. The mevalonate pathway, which starts with the synthesis of mevalonate by HMGR, has more branch pathways in plants than in most other organisms, leading to a tremendous variety of isoprenoid products. Evidence suggests that HMGR is an important control point for the synthesis of many of these plant isoprenoids, including some that are vital for primary metabolism and pest resistance. Plant HMGR activity responds in vivo to a variety of developmental and environmental signals, such as cell division, light, and infection. Plants regulate HMGR activity at the level of mRNA by differential induction of HMGR gene family members, and posttranslationally by enzyme modification. Calcium, calmodulin, and proteolytic degradation may also have a role in regulation of plant HMGR.