Decoding Ca2+ signals through plant protein kinases

Plants harbor four families of kinases that have been implicated in Ca2+ signaling (CDPKs, CRKs, CCaMKs, and SnRK3s). Although each family appears to respond to Ca2+ via different mechanisms, they all utilize Ca2+ sensors that bind Ca2+ through multiple EF-hands. The CDPK (Ca2+-dependent protein kinase) family is represented by the most genes, with 12 subfamilies comprised of 34 isoforms in Arabidopsis and 27 in rice. Some of the calcium-regulated kinases also show potential for regulation by lipid signals and kinase cascades. Thus, Ca2+-regulated kinases provide potential nodes of cross-talk for multiple signaling pathways that integrate Ca2+ signals into all aspects of plant growth and development.