2009 Fiscal Year Final Research Report

Analysis of physiological roles of ion channels in ER membrane

Research Project

Project/Area Number	20790173
Research Category	Grant-in-Aid for Young Scientists (B)
Allocation Type	Single-year Grants
Research Field	General physiology
Research Institution	Tohoku University
Principal Investigator	MURATA Yoshimichi Tohoku University, 大学院・医学系研究科, 助教 (60455780)
Project Period (FY)	2008 – 2009
Keywords	生体膜 / イオンチャネル
Research Abstract	We prepared nuclear envelopes (NEs) from mouse pancreatic acinar cells and observed MaxiK currents in the membrane subjected to the patch-clamp technique. The results indicate that the MaxiK channels are oriented in the ER membrane as their usual extracellular side faces to cytosol. These observation is inconsistent with the conventional understandings of the protein transport process. In this study, we examined the orientation of MaxiK channel in the ER membrane of the pancreatic acinar cells. We performed an immunofluorescent staining in our NE preparation using anti-Calnexin antibodies. Calnexin, an ER resident membrane protein, direscts C-terminus to the cytosol and N-terminus to the lumen. The antibody which binds to N-terminus of Calnexin showed the signal only when NE membrane was permeablilized. It supports the notion that the orientaion of our NE preparation itself would be intact. Collectively, we suggest that MaxiK channels of the mouse pancreatic acinar cells have unconventional orientation in the ER membrane.

(3 results)