Cytoplasmic dynein/dynactin mediates the assembly of aggresomes

• Published in: Cell motility and the cytoskeleton 2002-09, Vol.53 (1), p.26-38
• Main Authors: Johnston, Jennifer A., Illing, Michelle E., Kopito, Ron R.
• Format: Article
• Language: English
• Subjects: aggresome; Antigens - metabolism; Antigens - ultrastructure; Cells, Cultured; centrosome; Cystic Fibrosis Transmembrane Conductance Regulator - genetics; Cystic Fibrosis Transmembrane Conductance Regulator - metabolism; Cytoplasm - metabolism; Cytoplasm - ultrastructure; Dynactin Complex; dynein; Dyneins - metabolism; Dyneins - ultrastructure; Eukaryotic Cells - metabolism; Eukaryotic Cells - ultrastructure; Fluorescent Antibody Technique; Gene Expression Regulation - physiology; Green Fluorescent Proteins; Humans; Immunohistochemistry; Inclusion Bodies - metabolism; Inclusion Bodies - ultrastructure; Luminescent Proteins; Microscopy, Electron; microtubule; Microtubule-Associated Proteins - metabolism; Microtubule-Associated Proteins - ultrastructure; Microtubules - metabolism; Microtubules - ultrastructure; Molecular Motor Proteins - metabolism; Molecular Motor Proteins - ultrastructure; Neurodegenerative Diseases - metabolism; Neurodegenerative Diseases - physiopathology; Organelles - metabolism; Organelles - ultrastructure; Protein Folding; Protein Transport - physiology; proteolysis; Recombinant Fusion Proteins - genetics; Recombinant Fusion Proteins - metabolism
• ISSN: 0886-1544; 1097-0169
• DOI: 10.1002/cm.10057

Aggresomes are pericentrosomal cytoplasmic structures into which aggregated, ubiquitinated, misfolded proteins are sequestered. Misfolded proteins accumulate in aggresomes when the capacity of the intracellular protein degradation machinery is exceeded. Previously, we demonstrated that an intact microtubule cytoskeleton is required for the aggresome formation [Johnston et al., 1998: J. Cell Biol. 143:1883–1898]. In this study, we have investigated the involvement of microtubules (MT) and MT motors in this process. Induction of aggresomes containing misfolded ΔF508 CFTR is accompanied by a redistribution of the retrograde motor cytoplasmic dynein that colocalizes with aggresomal markers. Coexpression of the p50 (dynamitin) subunit of the dynein/dynactin complex prevents the formation of aggresomes, even in the presence of proteasome inhibitors. Using in vitro microtubule binding assays in conjunction with immunogold electron microscopy, our data demonstrate that misfolded ΔF508 CFTR associate with microtubules. We conclude that cytoplasmic dynein/dynactin is responsible for the directed transport of misfolded protein into aggresomes. The implications of these findings with respect to the pathogenesis of neurodegenerative disease are discussed. Cell Motil. Cytoskeleton 53:26–38, 2002. © 2002 Wiley‐Liss, Inc.