Author/Editor     Kabaso, Doron; Calejo, Ana I; Jorgačevski, Jernej; Kreft, Marko; Zorec, Robert; Iglič, Aleš
Title     Fusion pore diameter regulation by cations modulating local membrane anisotropy
Type     članek
Source     The scientific world journal
Vol. and No.     , št. 983138
Publication year     2012
Volume     str. 1-7
Language     eng
Abstract     The fusion pore is an aqueous channel that is formed upon the fusion of the vesicle membrane with the plasma membrane. Once the pore is open, it may close again (transient fusion) or widen completely (full fusion) to permit vesicle cargo discharge. While repetitive transient fusion pore openings of the vesicle with the plasma membrane have been observed in the absence of stimulation, their frequency can be further increased using a cAMP-increasing agent that drives the opening of nonspecific cation channels. Our model hypothesis is that the openings and closings of the fusion pore are driven by changes in the local concentration of cations in the connected vesicle. The proposedmechanism of fusion pore dynamics is considered as follows: when the fusion pore is closed or is extremely narrow, the accumulation of cations in the vesicle (increased cation concentration) likely leads to lipid demixing at the fusion pore. This process may affect local membrane anisotropy, which reduces the spontaneous curvature and thus leads to the opening of the fusion pore. Based on the theory of membrane elasticity, we used a continuum model to explain the rhythmic opening and closing of the fusion pore.
Descriptors     CELL MEMBRANE
MEMBRANE FUSION
CATIONS
ANISOTROPY
ION CHANNELS
CYCLIC AMP
COMPUTER SIMULATION