Calcium‐permeable channels in plant cells

Abstract

Calcium signal transduction is a central mechanism by which plants sense and respond to endogenous and environmental stimuli. Cytosolic Ca2+ elevation is achieved via two cellular pathways, Ca2+ influx through Ca2+ channels in the plasma membrane and Ca2+ release from intracellular Ca2+ stores. Because of the significance of Ca2+ channels in cellular signaling, interaction with the environment and developmental processes in plants, a great deal of effort has been invested in recent years with regard to these important membrane proteins. Because of limited space, in this review we focus on recent findings giving insight into both the molecular identity and physiological function of channels that have been suggested to be responsible for the elevation in cytosolic Ca2+ level, including cyclic nucleotide gated channels, glutamate receptor homologs, two‐pore channels and mechanosensitive Ca2+‐permeable channels. We provide an overview of the regulation of these Ca2+ channels and their physiological roles and discuss remaining questions.

Intracellular localization and physiological function of a rice Ca2+-permeable channel OsTPC1

“…1,2 Though electrophysiological studies have revealed several types of Ca 2+ -permeable channels localized at the plasma membrane (PM) and vacuolar membrane (VM) in many plant species, 3 their molecular identity are still largely unknown. Homologs of the major voltage-dependent Ca 2+ channels (VDCCs) are not found in plants.…”

“…Homologs of the major voltage-dependent Ca 2+ channels (VDCCs) are not found in plants. 3 In turn, the two-pore channel (TPC) family, originally isolated from rat, 4 is homologous to a half structure of the α1-subunit of vertebrate VDCCs. 5 Human TPCs mediate nicotinic acid adenine dinucleotide phosphate-induced Ca 2+ release from acidic organelles in HEK293 cells.…”

Multiple Calmodulin-binding Sites Positively and Negatively Regulate Arabidopsis CYCLIC NUCLEOTIDE-GATED CHANNEL12

“…Plant genomes examined to date lack homologs to animal voltage-gated cation channels and instead possess expanded families of ligand-gated cation channels, represented primarily by the ionotropic glutamate receptor-like channel and cyclic nucleotide-gated channel (CNGC) families (Mäser et al, 2001). CNGCs are nonselective cation channels that are hypothesized to function as Ca 2+ channels in plants (Dietrich et al, 2010;Jammes et al, 2011;Zelman et al, 2012) and are characterized by conserved structural components, including a short cytosolic N terminus, six transmembrane helices (S1-S6) with a pore-forming region between S5 and S6, and a cytosolic C terminus containing a cyclic nucleotide binding domain (CNBD; Kaupp and Seifert, 2002;Matulef and Zagotta, 2003). The CNBD mediates channel gating by cyclic nucleotide monophosphates such as cAMP and/or cGMP (Mäser et al, 2001;Kaupp and Seifert, 2002;Matulef and Zagotta, 2003;Kaplan et al, 2007;Zelman et al, 2012), though studies of this mechanism are largely restricted to animal isoforms.…”

A Cyclic Nucleotide-Gated Channel (CNGC16) in Pollen Is Critical for Stress Tolerance in Pollen Reproductive Development

“…In plants, cNMPs have been implicated in pathogen responses and salt and osmotic stresses (Jammes et al, 2011;Li et al, 2011;Ma and Berkowitz, 2011;Moeder et al, 2011).…”

“…Cyclic nucleotide monophosphates (cNMPs) 39,59-cyclic guanyl monophosphate (cGMP) and cAMP play key roles in the regulation of diverse cellular processes in eukaryotes and prokaryotes (Jammes et al, 2011), including biotic and abiotic stresses. In plants, cNMPs have been implicated in pathogen responses and salt and osmotic stresses (Jammes et al, 2011;Li et al, 2011;Ma and Berkowitz, 2011;Moeder et al, 2011).…”