Abstract
Transient depolarization of the plasma membrane (Kuchitsu et al.. 1993) and Ca2+ influx through the plasma membrane (Kurusu and Hamada et al.. 2010) are both rapidly induced at the initial steps of PAMP-tirggered immunity. However, ion channel molecules involved in these signaling events remain unknown. The two pore channel (TPC) family cation channels present both in plants and animals contain a putative voltage sensor domain. OsTPC1 has been suggested to play a role in the regulation of defense responses including activation of a MAP kinase and hypersensitive cell death induced by a xylanase elicitor, TvX, in rice cells (Kurusu et al.. 2005). We here established transgenic cell lines stably expressing apoaequorin, and analyzed TvX -induced cytosolic [Ca2+] changes in the wild type and Ostpc1 cells. Furthermore, we have isolated plasma membrane and vacuolar membrane fractions, and analyzed intracellular localization of OsTPC1 using its specific antibody. Possible localization and physiological roles of OsTPC1 will be discussed in comparison with its homologs in other plants and animals.
