Ca²⁺ homeostasis in plant cells: intracellular Ca²⁺ stores and Ca²⁺ binding proteins

Abstract

Plants share with animals the cellular machinery for regulating cytosolic free calcium concentrations. Nevertheless, the components involved in Ca²⁺ homeostasis have not yet been fully characterized in plants. In the last years there has been growing interest in identifying the plant counterparts of animal Ca²⁺ buffering proteins within intracellular Ca²⁺ storage pools. Evidence is accumulating for the expression of calreticulin as the main ER resident Ca²⁺ binding protein in higher plants. The fundamental role of this protein, involved in many cellular processes, is presented here in light of the latest findings obtained in animal cells.

Key Words:

• calreticulin
• calcium binding/storage proteins
• endoplasmic reticulum
• plant cells