Near-critical fluctuations and cytoskeleton-assisted phase separation lead to subdiffusion in cell membranes |
| |
Authors: | Ehrig Jens Petrov Eugene P Schwille Petra |
| |
Institution: | †Beckman Institute, University of Illinois at Urbana-Champaign, Champaign, Illinois;‡Center for Biophysics and Computational Biology, University of Illinois at Urbana-Champaign, Champaign, Illinois;§Howard Hughes Medical Institute and Department of Neurobiology, Harvard Medical School, Boston, Massachusetts;¶Équipe de Dynamique des Assemblages Membranaires, Centre National de la Recherche Scientifique UMR 7565, Nancy Université, Vandœuvre-lès-Nancy, France |
| |
Abstract: | Mechanosensitive channels, inner membrane proteins of bacteria, open and close in response to mechanical stimuli such as changes in membrane tension during osmotic stress. In bacteria, these channels act as safety valves preventing cell lysis upon hypoosmotic cell swelling: the channels open under membrane tension to release osmolytes along with water. The mechanosensitive channel of small conductance, MscS, consists, in addition to the transmembrane channel, of a large cytoplasmic domain (CD) that features a balloon-like, water filled chamber opening to the cytoplasm through seven side pores and a small distal pore. The CD is apparently a molecular sieve covering the channel that optimizes loss of osmolytes during osmoadaptation. We employ diffusion theory and molecular dynamics simulations to explore the transport kinetics of Glu− and K+ as representative osmolytes. We suggest that the CD indeed acts as a filter that actually balances passage of Glu− and K+, and possibly other positive and negative osmolytes, to yield a largely neutral efflux and, thereby, reduce cell depolarization in the open state and conserve to a large degree the essential metabolite Glu−. |
| |
Keywords: | |
本文献已被 ScienceDirect PubMed 等数据库收录! |
|