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

Abstract

Despite the molecular diversity of signaling components among plants and animals, Ca 2+ has been established as a common second messenger in most eukaryotic cells. 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. 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. 6 Arabidopsis AtTPC1 shows a slow-activating vacuolar cation channel activity 7,8 and be involved in the sucrose-induced Ca 2+ rise, 9 abscisic acid-induced repression of germination 10 and the stomatal response to extracellular Ca 2+ changes. 7,10 Tobacco NtTPC1s have roles in increasing Ca 2+ concentrations, defense-related gene expression, and regulation of hypersensitive cell death triggered by cryptogein, an elicitor from an oomycete, in tobacco BY-2 cells. 11 Rice and wheat TPC1s appear to function in responses to abiotic stresses. 12,13 Role of OsTPC1 in Xylanase Elicitor-Triggered Defense Responses in RiceCharacterization of the retrotransposon-insertional knockout mutant of rice Ostpc1 revealed that OsTPC1 affected the

Genome‐wide expressional and functional analysis of calcium transport elements during abiotic stress and development in rice

“…OsTPC1 was detected in tonoplast and tonoplast vesicles, which is supported by the prior study in Arabidopsis where AtTPC1 was localized to tonoplast [72]. Kurusu and co-workers recently expressed OsTPC1-GFP in tobacco BY-2 cells and it was found to be localized to the vacuolar membrane [73]. However, Arabidopsis TPC was also detected partly in the plasma membrane when it was expressed in tobacco [74].…”

On the cellular site of two‐pore channel TPC1 action in the Poaceae

“…In order to revisit the localization and function of OsTPC1 we transiently transformed the Arabidopsis loss‐of‐ tpc‐1‐2 mutant with OsTPC1 . In previous studies N‐terminal GFP labeled OsTPC1 was localized in the plasma membrane of onion epidermal cells as well as the rice cell culture, but very recently C‐terminal GFP tagged OsTPC1 in the vacuolar membrane of tobacco BY‐2 cells (Kurusu et al ., , ; Hamada et al ., ). In all of these experiments expression of OsTPC1 was driven by the CaMV 35S promoter.…”

Meristematic Connectome: A Cellular Coordinator of Plant Responses to Environmental Signals?

“…Moreover, mechanical forces can influence plasma membranes, microtubules, actin filaments and calcium channels (CaC) and further, it is known that tension force can affect the function of cyclic nucleotide gated channels (CNGCs) and mechanosensitive calcium channels (MCA) through a membrane thinning effect [46][47][48][49][50].…”