Keratin-containing inclusions affect cell morphology and distribution of cytosolic cellular components.
Many neurodegenerative diseases are characterized by the presence of protein aggregates bundled with intermediate filaments (IFs) and similar structures, known as Mallory bodies (MBs), are observed in various liver diseases. IFs are anchored at desmosomes and hemidesmosomes, however, interactions with other intercellular junctions have not been determined. We investigated the effect of IF inclusions on junction-associated and cytosolic proteins in various cultured cells. We performed gene transfection of the green fluorescent protein (GFP)-tagged cytokeratin (CK) 18 mutant arg89cys (GFP-CK18 R89C) in cultured cells and observed CK aggregations as well as loss of IF networks. Among various junction-associated proteins, zonula occludens-1 and beta-catenin were colocalized with CK aggregates on immunofluorescent analyses. Similar results were obtained on immunostaining for cytosolic proteins, 14-3-3 zeta protein, glucose-6-phosphate dehydrogenase and DsRed. E-cadherin, a basolateral membrane protein in polarized epithelia, was present on both the apical and basolateral domains in GFP-CK18 R89C-transfected cells. Furthermore, cells containing CK aggregates were significantly larger than GFP-tagged wild type CK18 (GFP-WT CK18)-transfected or non-transfected cells (P < 0.01) and sometimes their morphology was significantly altered. Our data indicate that CK aggregates affect not only cell morphology but also the localization of various cytosolic components, which may affect the cellular function.
Hanada
Shinichiro
S
Second Department of Medicine, Kurume University School of Medicine, Liver Cancer Division, Research Center for Innovative Cancer Therapy, Kurume University, 67 Asahi-machi, Kurume 830-0011, Japan. hanadas@med.kurume-u.ac. jp
Harada
Masaru
M
Kumemura
Hiroto
H
Omary
M Bishr
MB
Kawaguchi
Takumi
T
Taniguchi
Eitaro
E
Koga
Hironori
H
Yoshida
Takafumi
T
Maeyama
Michiko
M
Baba
Shinji
S
Ueno
Takato
T
Sata
Michio
M
D048948:14-3-3 Proteins / Q000378:metabolism; D000818:Animals; D002460:Cell Line; D045744:Cell Line, Tumor; D048430:Cell Shape / Q000502:physiology; D048429:Cell Size; D003600:Cytosol / Q000378:metabolism* / Q000473:pathology / Q000648:ultrastructure; D004285:Dogs; D004847:Epithelial Cells / Q000378:metabolism* / Q000473:pathology / Q000648:ultrastructure; D005455:Fluorescent Antibody Technique; D005954:Glucosephosphate Dehydrogenase / Q000378:metabolism; D049452:Green Fluorescent Proteins; D006801:Humans; D002479:Inclusion Bodies / Q000378:metabolism* / Q000473:pathology / Q000648:ultrastructure; D007365:Intercellular Junctions / Q000378:metabolism* / Q000473:pathology / Q000648:ultrastructure; D007382:Intermediate Filaments / Q000378:metabolism* / Q000473:pathology / Q000648:ultrastructure; D007633:Keratins / Q000235:genetics / Q000378:metabolism*; D008565:Membrane Proteins / Q000378:metabolism; D046529:Microscopy, Electron, Transmission; D009154:Mutation / Q000235:genetics; D014162:Transfection
D048948:14-3-3 Proteins; D008565:Membrane Proteins; D049452:Green Fluorescent Proteins; D007633:Keratins; D005954:Glucosephosphate Dehydrogenase