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The C-terminal region of ahnak provides a link between cardiac L-type Ca2+ calcium channels and the actin-based cytoskeleton

Item Type:Article
Title:The C-terminal region of ahnak provides a link between cardiac L-type Ca2+ calcium channels and the actin-based cytoskeleton
Creators Name:Hohaus, A., Person, V., Behlke, J., Schaper, J., Morano, I. and Haase, H.
Abstract:Ahnak is a ubiquitously expressed giant protein of 5643 amino acids implicated in cell differentiation and signal transduction. In a recent study, we demonstrated the association of ahnak with the regulatory {beta}2 subunit of the cardiac L-type Ca2+ channel. Here we identify the most carboxyl-terminal ahnak region (aa 5262-5643) to interact with recombinant {beta}2a as well as with {beta}2 and {beta}1a isoforms of native muscle Ca2+ channels using a panel of GST fusion proteins. Equilibrium sedimentation analysis revealed Kd values of 55 ± 11 nM and 328 ± 24 nM for carboxyl-terminal (aa 195-606) and amino-terminal (aa 1-200) truncates of the {beta}2a subunit, respectively. The same carboxyl terminal ahnak region (aa 5262-5643) bound to G-actin and cosedimented with F-actin. Confocal microscopy of human left ventricular tissue localized the carboxyl terminal ahnak portion to the sarcolemma including the T-tubular system and the intercalated disks of cardiomyocytes. These results suggest that ahnak provides a structural basis for the subsarcolemmal cytoarchitecture and confers the regulatory role of the actin-based cytoskeleton to the L-type Ca2+ channel.
Keywords:{Beta}3 Subunit, Cardiomyocytes, L-Type Calcium Channel, Protein-Protein Interaction, Animals, Swine
Source:FASEB Journal
ISSN:0892-6638
Publisher:Federation of American Societies for Experimental Biology
Volume:16
Number:10
Page Range:1205-1216
Date:August 2002
Official Publication:https://doi.org/10.1096/fj.01-0855com
PubMed:View item in PubMed

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