Cytoplasmic dynein regulation by subunit heterogeneity and its role in apical transport.
Despite the existence of multiple subunit isoforms for the microtubule motor cytoplasmic dynein, it has not yet been directly shown that dynein complexes with different compositions exhibit different properties. The 14-kD dynein light chain Tctex-1, but not its homologue RP3, binds directly to rhodopsin's cytoplasmic COOH-terminal tail, which encodes an apical targeting determinant in polarized epithelial Madin-Darby canine kidney (MDCK) cells. We demonstrate that Tctex-1 and RP3 compete for binding to dynein intermediate chain and that overexpressed RP3 displaces endogenous Tctex-1 from dynein complexes in MDCK cells. Furthermore, replacement of Tctex-1 by RP3 selectively disrupts the translocation of rhodopsin to the MDCK apical surface. These results directly show that cytoplasmic dynein function can be regulated by its subunit composition and that cytoplasmic dynein is essential for at least one mode of apical transport in polarized epithelia.
Tai
A W
AW
Department of Cell Biology and Anatomy, The Margaret M. Dyson Vision Research Institute, Weill Medical College of Cornell University, New York, New York 10021, USA.
Chuang
J Z
JZ
Sung
C H
CH
D000818:Animals; D001667:Binding, Competitive / Q000187:drug effects; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism; D003593:Cytoplasm / Q000378:metabolism*; D004285:Dogs; D015536:Down-Regulation; D004398:Dyneins / Q000378:metabolism*; D004847:Epithelial Cells / Q000166:cytology / Q000378:metabolism; D005136:Eye Proteins; D005455:Fluorescent Antibody Technique; D007668:Kidney / Q000166:cytology / Q000378:metabolism; D046911:Macromolecular Substances; D008565:Membrane Proteins / Q000378:metabolism; D008868:Microtubule Proteins / Q000235:genetics / Q000378:metabolism; D008869:Microtubule-Associated Proteins; D008870:Microtubules / Q000187:drug effects / Q000378:metabolism; D015739:Nocodazole / Q000494:pharmacology; D009687:Nuclear Proteins; D009842:Oligopeptides; D010455:Peptides / Q000235:genetics; D011485:Protein Binding / Q000187:drug effects; D021122:Protein Subunits; D021381:Protein Transport / Q000502:physiology; D011506:Proteins / Q000235:genetics / Q000378:metabolism / Q000494:pharmacology; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D012243:Rhodopsin / Q000378:metabolism; D014162:Transfection; D056427:t-Complex Genome Region
D005136:Eye Proteins; D046911:Macromolecular Substances; D008565:Membrane Proteins; D008868:Microtubule Proteins; D008869:Microtubule-Associated Proteins; D009687:Nuclear Proteins; D009842:Oligopeptides; D010455:Peptides; D021122:Protein Subunits; D011506:Proteins; C099929:RPGR protein, human; D011993:Recombinant Fusion Proteins; D012243:Rhodopsin; C085706:FLAG peptide; D004398:Dyneins; D015739:Nocodazole