Ca2+ and calmodulin-dependent inactivation of the L-type Ca2+ channel and its mutants

2015 Fiscal Year Final Research Report

• Project/Area Number: 25460294
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: General physiology
• Research Institution: Kagoshima University
• Principal Investigator: Minobe Etsuko 鹿児島大学, 医歯学域医学系, 講師 (00448581)
• Research Collaborator: MORI Masayuki 京都大学, 大学院工学研究科, 准教授 (80342640)
• Project Period (FY): 2013-04-01 – 2016-03-31
• Keywords: カルシウムチャネル / カルモジュリン / パッチクランプ法 / inside-out / カルシウムイオン / ATP / run-down / リン酸化

Outline of Final Research Achievements

Calmodulin (CaM) binds to the channel directly and change channel activity in a Ca2+-dependent manner. We reported that the channel activity increases and decreases in a CaM-concentration-dependent manner. Based on our experiments, we propose a model for the regulation of Cav1.2 channel by two CaM binding sites, in which CaM binds to an activation site and then another CaM binds to an inactivation site. To test this hypothesis, we measured the channel activity of C-terminal deletion channel linked with CaM (CaM-linked-channel) and linked with Ca2+-insensitive CaM mutant (CaMmut-linked-channel), using the patch-clamp technique. In the whole-cell recording, the inactivation was diminished in CaMmut-linked-channel. In the inside-out recording, Ca2+-dependent inactivation was observed in the CaM-linked-channel, but not in the CaMmut-linked-channel. The CaM concentration-dependent inactivation was observed in both channels. These results support two-CaM binding site model.

Free Research Field

電気生理学、分子生物学