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Biochemistry Research International
Volume 2012, Article ID 497572, 11 pages
http://dx.doi.org/10.1155/2012/497572
Research Article

Caveolin 3, Flotillin 1 and Influenza Virus Hemagglutinin Reside in Distinct Domains on the Sarcolemma of Skeletal Myofibers

1Department of Anatomy and Cell Biology, Institute of Biomedicine, University of Oulu, P.O. Box 5000, Aapistie 7, 90014 Oulu, Finland
2Department of Health Sciences, University of Jyväskylä, P.O. Box 35, 40014 Jyväskylä, Finland

Received 12 August 2011; Revised 14 October 2011; Accepted 21 October 2011

Academic Editor: Jean-Francois Jasmin

Copyright © 2012 Mika Kaakinen et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

We examined the distribution of selected raft proteins on the sarcolemma of skeletal myofibers and the role of cholesterol environment in the distribution. Immunofluorescence staining showed that flotillin-1 and influenza hemagglutinin exhibited rafts that located in the domains deficient of the dystrophin glycoprotein complex, but the distribution patterns of the two proteins were different. Cholesterol depletion from the sarcolemma by means of methyl-β-cyclodextrin resulted in distorted caveolar morphology and redistribution of the caveolin 3 protein. Concomitantly, the water permeability of the sarcolemma increased significantly. However, cholesterol depletion did not reshuffle flotillin 1 or hemagglutinin. Furthermore, a hemagglutinin variant that lacked a raft-targeting signals exhibited a similar distribution pattern as the native raft protein. These findings indicate that each raft protein exhibits a strictly defined distribution in the sarcolemma. Only the distribution of caveolin 3 that binds cholesterol was exclusively dependent on cholesterol environment.