Jasmonates: Regulation of Ca2+-ATPase and role in calcium homeostasis

Abstract

The active transport of Ca²⁺ across the membrane of sarcoplasmic reticulum has received much attention for several decades from biochemical and biophysical points of view.  The protein composition of this membrane system has been extensively studied and four major proteins have been identified. The molecular mechanisms by which the chemical energy of ATP hydrolysis is channelled into the vectorial movement of  Ca²⁺ via the  Ca²⁺-transporting ATPases have also been the subject of intensive research for several years.  As a result, a great deal of information on the biochemical properties of the enzymes involved have accumulated.  However, the precise mechanism by which these enzymes translocate Ca²⁺ is just beginning to emerge as a result of the recent report on the crystal structure of skeletal muscle sarcoplasmic reticulum Ca²⁺-ATPase.  The intracelular Ca²⁺ concentration controls (directly or indirectly) many important cellular processes such as muscle contraction and relaxation, nervous excitation, exocrine and endocrine secretions, as well as complicated processes such as cell proliferation and fertilization.  The discovery of the molecular function of jasmonates in regulating calcium homeostasis has given new insights into this exciting field. The emergence of jasmonates as key players in integrating intracellular calcium homeostasis, and their roles in our understanding of the calcium pumping event, is the main focus of this review.