title: Aggregate-prone desmin mutations impair mitochondrial calcium uptake in primary myotubes.
abstract: Desmin, being a major intermediate filament of mature muscle cell, interacts with mitochondria within the cell and participates in mitochondria proper localization. The goal of the present study was to assess the effect of aggregate-prone and non-aggregate-prone desmin mutations on mitochondrial calcium uptake. Primary murine satellite cells were transduced with lentiviruses carrying desmin in wild type or mutant form, and were induced to differentiate into myotubes. Four mutations resulting in different degree of desmin aggregates formation were analyzed. Tail domain mutation Asp399Tyr has the mildest impact on desmin filament polymerization, rod domain mutation Ala357Pro causes formation of large aggregates composed of filamentous material, and Leu345Pro and Leu370Pro are considered to be the most severest in their impact on desmin polymerization and structure. For mitochondrial calcium measurement cells were loaded with rhod 2-AM. We found that aggregate-prone mutations significantly decreased [Ca(2+)]mit, whereas non-aggregate-prone mutations did not decrease [Ca(2+)]mit. Moreover aggregate-prone desmin mutations resulted in increased resting cytosolic [Ca(2+)]. However this increase was not accompanied by any alterations in sarcoplasmic reticulum calcium release. We suggest that the observed decline in [Ca(2+)]mit was due to desmin aggregate accumulation resulting in the loss of desmin mitochondria interactions.
authors.affiliation: Department of Women's and Children's Health, Karolinska Institutet, Stockholm, Sweden; Center for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden; Federal Almazov Medical Research Centre, St-Petersburg, Russia. Electronic address: natalia.smolina@ki.se.
authors.forename: Natalia
authors.initials: N
authors.lastname: Smolina
authors.affiliation: Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Joseph
authors.initials: J
authors.lastname: Bruton
authors.affiliation: Department of Women's and Children's Health, Karolinska Institutet, Stockholm, Sweden; Center for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Gunnar
authors.initials: G
authors.lastname: Sjoberg
authors.affiliation: Department of Women's and Children's Health, Karolinska Institutet, Stockholm, Sweden; Center for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden; Federal Almazov Medical Research Centre, St-Petersburg, Russia.
authors.forename: Anna
authors.initials: A
authors.lastname: Kostareva
authors.affiliation: Department of Women's and Children's Health, Karolinska Institutet, Stockholm, Sweden; Center for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Thomas
authors.initials: T
authors.lastname: Sejersen
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002478:Cells, Cultured; D003599:Cytoskeleton / Q000378:metabolism*; D003893:Desmin / Q000235:genetics* / Q000378:metabolism; D006575:Heterocyclic Compounds, 3-Ring / Q000378:metabolism; D008297:Male; D008810:Mice, Inbred C57BL; D008928:Mitochondria / Q000378:metabolism*; D018485:Muscle Fibers, Skeletal / Q000378:metabolism*; D009154:Mutation / Q000235:genetics*
chemical_list: D003893:Desmin; D006575:Heterocyclic Compounds, 3-Ring; C068483:rhod-2; D002118:Calcium
keywords: Calcium; Desmin; Mitochondria; Myotube; Satellite cell