Paper Information

Title:  EFFECTS OF ADP-MG ON SINGLE POTASSIUM CHANNEL OF ROUGH ENDOPLASMIC RETICULUM INCORPORATED IN BILAYER LIPID MEMBRANE
Type: SPEECH
Author(s): ELIASI A.,ASHRAFPOUR M.,SAGHIRI R.
 
 
 
Name of Seminar: IRANIAN CONGRESS OF PHYSIOLOGY AND PHARMACOLOGY
Type of Seminar:  CONGRESS
Sponsor:  PHYSIOLOGY AND PHARMACOLOGY SOCIETY, MASHHAD UNIVERSITY OF MEDICAL SCIENCE
Date:  2007Volume 18
 
 
Abstract: 

Introduction: Ion channels in mitochondria and RER have important roles in intracellular signaling. Recent studies demonstrate that mitochondrial potassium channels participate in cell death and apoptosis, but there isn't any information about pharmacological and electrophysiological characteristics of RER potassium channel. Our former studies demonstrated low opening frequency of RER potassium channel in voltage less than 30 mV. Therefore, it is important to find physiological factors to increase channel open probability. The channel phosphorylation is one of the most important factors to control channel gating, thus purpose of this study is to consider effect of ADP-Mg on channel behavior.
Methods: We used single channel recording method after incorporation of microsomes into phosphatydilcholine bilayer lipid membrane. Subsequently, PC extraction by singleton protocol, BLM making in 250 µM holes by Muller technique and RER extraction through Can method were carried out. After incorporation of protein channel in BLM, channel activity was recorded and data have been interpreted using Noise Free Markov's analysis and clampfit9 software.
Results: our results showed that ADP-Mg 2.5 mM didn't affect RER potassium channel activities at voltage of +40mV. While, adding ADP-Mg in cytoplasmic face increased significantly mean open probability (Po) from 0.02 to 0.7 at different voltages (-10, 0, and +20 mV) less than reverse potential (+30 mV).
Discussion: This study demonstrates ADP-Mg increased RER potassium channel activity as voltage dependent manner. Channel phosphorylation induced very high Po at low voltages near ER physiological resting membrane potential. It seems this channel will be more activated by phosphorylation and controls by metabolic variables and probably involved in ER lumen homeostasis and cell protection.

 
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