Proteinaceous pore

The CT channels are essential for any form of CT movement, and consequently for CT-associated processes. These proteinaceous pores in the plasma membrane or in intracellular organelles have a function for ion homeostasis, ion transport, cell volume and regulation of electrical excitability (Jentsch et al. 2002). 

Transmembrane ionic currents involve proteinaceous membrane pores Na+, Ca2+, and 1<+ channels. In A, the phasic change in the functional state of Na+ channels during an action potential is illustrated. 

Fisher, P. A., Berrios, M., and Blobel, G. (1982). Isolation and characterization of a proteinaceous subnuclear fraction composed of nuclear matrix, peripheral lamina and nuclear pore complexes from embryos of Drosophila melanogaster J. Cell Biol 92, 674-686. 

The nuclear lamina lies subjacent to the inner nuclear membrane (see Fig. 1 in the chapter by Berrios, this volume) it is a proteinaceous network composed of intermediate filament-like fibrils and is thought to provide structural support to the interphase nucleus. Results of previous studies suggest that the lamina binds specific loci on chromosomes and may thus play a role in organizing the genome within nuclei (Lud rus et al., 1992,1994 Baricheva et al, 19% Zhao et aL, 19% Rzepecki et al., 1997 Sharakhov et al., 1997). Other results suggest that the lamina may also be involved in DNA replication (see, e.g., Moir et al., 1994). The lamina appears to anchor nuclear pore complexes physically. 

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