Molecular remodeling of ion channels due to alternative splicing and alterations in expression of ion channel genes is associated with diverse in vitro effects and may represent new facets of channelopathy. By combining the laser-capture microdissection of identified cells in live tissue sections with RT-PCR analysis of transcripts, we found that in arterial vascular smooth muscle cells, atherosclerosis causes replacement of multiple exon-21 isoforms of the Cav1.2 calcium channel pore-forming Cav1.2 alpha1C subunit by a single exon-22 Cav1.2 alpha1C isoform. This atherosclerotic Cav1.2 alpha1C splice variant is characteristic for proliferating vascular smooth muscle cells and shows significantly different electrophysiological and pharmacological properties (Tiwari et al., 2006).? ? We use fluorescence resonance energy transfer combined with patch clamp to monitor voltage-dependent rearrangements of ion channel structures (Kobrinsky 2006) and spatio-temporal properties of signaling microdomains associated with calcium channel activity (Mager et al., 2007). The multi-resolution properties of the continuous wavelet transform suggest that it might have use to identify the spatio-temporal spectral content and discontinuities across scales of organization in biological signals and images. To identify signaling macro- and micro-domains in cell plasma membrane and cytosolic compartments, a technique that utilizes the wavelet transform has been extended to two-dimensional analysis of time-lapse fluorescence and/or FRET images. Illustrating successful application to the analysis of intracellular compartments, the two-dimensional wavelet transform was applied to identify signaling domains of CREB-induced transcriptional activation in the nuclei of COS1 cells (Mager et al., 2007). This approach gives a unique opportunity to characterize complex cellular signaling and protein-protein interactions within localized cytoplasmic domains.
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