Published online
doi:10.1083/jcb.200711058
The Journal of Cell Biology, Vol. 181, No. 4, 667-681
The Rockefeller University Press, 0021-9525 $30.00
© Konieczny et al.
Myofiber integrity depends on desmin network targeting to Z-disks and costameres via distinct plectin isoforms
Patryk Konieczny1,
Peter Fuchs1,
Siegfried Reipert1,
Wolfram S. Kunz2,3,
Anikó Zeöld1,
Irmgard Fischer1,
Denise Paulin4,
Rolf Schröder5, and
Gerhard Wiche1
1 Max F. Perutz Laboratories, Department of Molecular Cell Biology, University of Vienna, A-1030 Vienna, Austria
2 Department of Epileptology and 3 Life & Brain Center, University of Bonn, D-53105 Bonn, Germany
4 Biologie Moléculaire de la Différenciation, Université Paris 7, 75005 Paris, France
5 Institute of Neuropathology, Friedrich-Alexander University, D-91054 Erlangen, Germany
Correspondence to G. Wiche: gerhard.wiche{at}univie.ac.at
Dysfunction of plectin, a 500-kD cytolinker protein, leads to skin blistering and muscular dystrophy. Using conditional gene targeting in mice, we show that plectin deficiency results in progressive degenerative alterations in striated muscle, including aggregation and partial loss of intermediate filament (IF) networks, detachment of the contractile apparatus from the sarcolemma, profound changes in myofiber costameric cytoarchitecture, and decreased mitochondrial number and function. Analysis of newly generated plectin isoform–specific knockout mouse models revealed that IF aggregates accumulate in distinct cytoplasmic compartments, depending on which isoform is missing. Our data show that two major plectin isoforms expressed in muscle, plectin 1d and 1f, integrate fibers by specifically targeting and linking desmin IFs to Z-disks and costameres, whereas plectin 1b establishes a linkage to mitochondria. Furthermore, disruption of Z-disk and costamere linkages leads to the pathological condition of epidermolysis bullosa with muscular dystrophy. Our findings establish plectin as the major organizer of desmin IFs in myofibers and provide new insights into plectin- and desmin-related muscular dystrophies.
Abbreviations used in this paper: β-DG, β-dystroglycan; CNF, centrally nucleated fiber; COX, cytochrome c oxidase; CSA, cross-sectional area; DGC, dystrophin–glycoprotein complex; DRM, desmin-related myopathy; EBD, Evans blue dye; EB-MD, epidermolysis bullosa with muscular dystrophy; EDL, extensor digitorum longus; H & E, hematoxylin and eosin; IF, intermediate filament; MCK, muscle creatine kinase; nNOS, neuronal nitric oxide synthase; SDH, succinate dehydrogenase; WT, wild type.
© 2008 Konieczny et al. This article is distributed under the terms of an Attribution–Noncommercial–Share Alike–No Mirror Sites license for the first six months after the publication date (see http://www.jcb.org/misc/terms.shtml). After six months it is available under a Creative Commons License (Attribution–Noncommercial–Share Alike 3.0 Unported license, as described at http://creativecommons.org/licenses/by-nc-sa/3.0/).

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