Channel clustering

Hueh, Y., Kim, E. and Sheng, M. Disulfide-linked head-to-head multimerization in the mechanism of ion channel clustering by PSD-95. Neuron 18 803-814,1997. 

The wings extend sideways from the body domains perpendicular to the central symmetry axis of the tetramer and could participate in the binding to some receptors (see Sections 2.3 and 4). They also seem to mediate homotypic interactions, causing tetramers to assemble into flat 2D crystals, often containing large numbers of tetramers (Lunev et al. 1991). These lattices could underlie the frequently described phenomenon of a-LTX channel clusterization (Robello et al. 1987 Krasilnikov and Sabirov 1992 Filippov et al. 1994 Van Renterghem et al. 2000). 

Dependence on Ca2+ Sensing Latency Times, Ca2+ Channel Kinetic Parameters, and Channel Clustering... 

To investigate numerically the dependence of exocytosis probability on ion channel clustering and to test our theoretical results, we carried out numerical simulations on a system of identical and independent two-state channels. A set of dwell times for a single channel in shut and open states was generated with the help of a source equation ... 

For every individual simulation process, i.e. for each size of channel cluster, the waiting time for the event at least one channel is open for f/ was detected this was repeated 400 times. Then the distribution of waiting times, w (t) was estimated from binned data. An example of a histogram obtained is seen in Fig. 11.3 for a cluster that contains three channels, with ma = 1.9 ms and ms = 5 ms. 

The simulation data were extended for other multiple channel systems, up to ten channels these data are summarized in Figs. 11.4 to 11.6. The importance of channel clustering in case of large delay times is obvious from these figures, e.g. in the case of a 10 ms latency time, depolarizing pulses shorter than 20 ms practically do not induce exocytosis, even with clusters containing ten channels. 

During myelin repair, a thinner myelin sheath is produced with shorter intern-odes, but efficient nerve conduction is produced (Smith et al., 1979). The aggregation of nodal, paranodal, and juxtaparanodal axonal molecules recapitulates the pattern observed during development with the initial step being Nay channel clustering (Coman et al., 2005 Ogawa et al., 2006). 

R.J. Kittel et ah, Bruchpilot promotes active zone assembly, Ca2+-channel clustering, and vesicle release. Science 312, 1051-1054 (2006)... 

Xenopus Oocytes Potassium channel clustering by the cytoskeleton Honore etal., 1992... 

Tra r-homophihc cell adhesion may occur between axonal and glial cell Na channel j subunits. This putative adhesion may also contribute to Na channel clustering in nodes of Ranvier during the process of myelination. 

Kim E, Naisbitt S, Hsueh Y-P, Rao A, Rothschild A et al. (1997) GKAP, a novel synaptic protein that interacts with the guanylate kinase-like domain of the PSD-95/SAP90 family of channel clustering molecules. J Cell Biol 136 669-67S. 

Sheng M (1996) PDZs and receptor/channel clustering rounding up the latest suspects. Neuron 77 575-578. 

We will introduce a Ca model for an IP3 receptor channel cluster in the next section. It serves as input for a master equation in section... 

We have derived a master equation and two Fokker-Planck equations for channel cluster behavior in IP3 mediated Ca dynamics. Among the different approaches to approximate a master equation by a Fokker-Planck equation we have chosen van Kampen s II expansion and an ansatz based... 

R. Thul and M. Falcke. Release currents of IP3 receptor channel clusters and concentration profiles. Biophys. J., 86 2660-2673, 2004. 

Shin, H., Hsueh, Y. P, Yang, F. C., Kim, E., and Sheng, M. (2000). An intramolecular interaction between Src homology 3 domain and guanylate kinase-like domain required for channel clustering hy postsynaptic density-95/SAP90./. Neurosci. 20, 3580-3587. 

Now that the contact angle and channel-size distribution are known, the fraction of expanded channels can be calculated as a function of the hydraulic pressure. In accordance with the physical model, the expanded channel-cluster network is treated as a bundle of capillaries. To calculate S, a critical... 

Savtchenko, L. R Gogan, P. Korogod, S. M. Tyc-Dumont, S. Imaging stochastic spatial variability of active channel clusters during excitation of single neurons. Neurosci. Res. 2001, 39, 431-446. 

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