Novel types of Ca2+ release channels participate in the secretory cycle of Paramecium cells.
نویسندگان
چکیده
A database search of the Paramecium genome reveals 34 genes related to Ca(2+)-release channels of the inositol-1,4,5-trisphosphate (IP(3)) or ryanodine receptor type (IP(3)R, RyR). Phylogenetic analyses show that these Ca(2+) release channels (CRCs) can be subdivided into six groups (Paramecium tetraurelia CRC-I to CRC-VI), each one with features in part reminiscent of IP(3)Rs and RyRs. We characterize here the P. tetraurelia CRC-IV-1 gene family, whose relationship to IP(3)Rs and RyRs is restricted to their C-terminal channel domain. CRC-IV-1 channels localize to cortical Ca(2+) stores (alveolar sacs) and also to the endoplasmic reticulum. This is in contrast to a recently described true IP(3) channel, a group II member (P. tetraurelia IP(3)R(N)-1), found associated with the contractile vacuole system. Silencing of either one of these CRCs results in reduced exocytosis of dense core vesicles (trichocysts), although for different reasons. Knockdown of P. tetraurelia IP(3)R(N) affects trichocyst biogenesis, while CRC-IV-1 channels are involved in signal transduction since silenced cells show an impaired release of Ca(2+) from cortical stores in response to exocytotic stimuli. Our discovery of a range of CRCs in Paramecium indicates that protozoans already have evolved multiple ways for the use of Ca(2+) as signaling molecule.
منابع مشابه
Novel Types of Ca Release Channels Participate in the Secretory Cycle of Paramecium Cells †
متن کامل
Acid-sensing ion channel 1a regulates the survival of nucleus pulposus cells in the acidic environment of degenerated intervertebral discs
Objective(s): Activation of acid-sensing ion channel 1a (ASIC1a) is responsible for tissue injury caused by acidosis in nervous systems. But its physiological and pathological roles in nucleus pulposus cells (NPCs) are unclear. The aim of this study is to investigate whether ASIC1a regulates the survival of NPCs in the acidic environment of degenerated discs. Materials and Methods: NPCs were i...
متن کاملThe Effect of “Teucrium polium L.” Extracts on Insulin Release from in situ Isolated Perfused Rat Pancreas in a Newly Modified Isolation Method: the Role of Ca2+ and K+ Channels
Background: “Teucrium polium L.” (TP) has been long recommended in Iranian folk medicine for its anti-diabetic activities. We attempt here to evaluate the effect of TP extract on insulin secretion in rat pancreas. Methods: Rat pancreas was isolated in situ and perfused with Krebs solution containing low glucose (LG, 2.8 mM) or high glucose (HG, 16.7 mM) as perfusate. The aqueous extract (Aq. E)...
متن کاملAn exocytotic mutant of ParalJ 1 eciulJ 1 caudatulJ 1 : membrane fusion without secretory contents release
This is a detailed characterization of a secretory mutant incapable of releasing secretory contents despite normal exocytotic membrane fusion performance. Trichocyst non-discharge strain tnd1 of Paramecium caudatum and its wildtype (wt) both show a transient cortical [Ca+l; increase and exocytotic membrane fusion in response to the polyamine secretagogue, aminoethyldextran (AEO), or to caffeine...
متن کاملFocal Adhesion Kinase (FAK) Involvement in Human Endometrial Remodeling During the Menstrual Cycle
Background: Endometrial remodeling occurs during each menstrual cycle in women. Reports have shown that, in a variety of cell types, processes such as proliferation, signaling complex formation and extra cellular matrix remodeling require a cytoplasmic tyrosine kinase, focal adhesion kinase (FAK). The present study has focused on the expression pattern of FAK in human endometrium during the men...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
- Molecular and cellular biology
دوره 29 13 شماره
صفحات -
تاریخ انتشار 2009