Localization of Tctex-1, a cytoplasmic dynein light chain, to the Golgi apparatus and evidence for dynein complex heterogeneity.
To date, much attention has been focused on the heavy and intermediate chains of the multisubunit cytoplasmic dynein complex; however, little is known about the localization or function of dynein light chains. In this study, we find that Tctex-1, a light chain of cytoplasmic dynein, localizes predominantly to the Golgi apparatus in interphase fibroblasts. Immunofluorescent staining reveals striking juxtanuclear staining characteristic of the Golgi apparatus as well as nuclear envelope and punctate cytoplasmic staining that often decorates microtubules. Tctex-1 colocalization with Golgi compartment markers, its distribution upon treatment with various pharmacological agents, and the cofractionation of Tctex-1-associated membranes with Golgi membranes are all consistent with a Golgi localization. The distribution of Tctex-1 in interphase cells only partially overlaps with the dynein intermediate chain and p150(Glued) upon immunofluorescence, but most of Tctex-1 is redistributed onto mitotic spindles along with other dynein/dynactin subunits. Using sequential immunoprecipitations, we demonstrate that there is a subset of Tctex-1 not associated with the intermediate chain at steady state; the converse also appears to be true. Distinct populations of dynein complexes are likely to exist, and such diversity may occur in part at the level of their light chain compositions.
Tai
A W
AW
Department of Cell Biology and Anatomy, Margaret M. Dyson Vision Research Institute, Cornell University Medical College, New York, New York 10021, USA.
Chuang
J Z
JZ
Sung
C H
CH
D000595:Amino Acid Sequence; D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001483:Base Sequence; D020126:Brefeldin A; D002417:Cattle; D002478:Cells, Cultured; D003001:Cloning, Molecular; D003517:Cyclopentanes / Q000494:pharmacology; D015638:Cytochalasin D / Q000494:pharmacology; D000072159:Dynactin Complex; D004398:Dyneins / Q000737:chemistry*; D006056:Golgi Apparatus / Q000737:chemistry*; D007150:Immunohistochemistry; D047908:Intracellular Signaling Peptides and Proteins; D018942:Macrolides; D008869:Microtubule-Associated Proteins / Q000378:metabolism; D008969:Molecular Sequence Data; D015739:Nocodazole / Q000494:pharmacology; D009687:Nuclear Proteins / Q000378:metabolism*; D011233:Precipitin Tests; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D008941:Spindle Apparatus / Q000378:metabolism; D044767:Ubiquitin-Protein Ligases; D056427:t-Complex Genome Region
D000900:Anti-Bacterial Agents; D003517:Cyclopentanes; C000606360:DCTN1 protein, human; D000072159:Dynactin Complex; D047908:Intracellular Signaling Peptides and Proteins; D018942:Macrolides; D008869:Microtubule-Associated Proteins; D009687:Nuclear Proteins; D020126:Brefeldin A; D015638:Cytochalasin D; C116196:PPP1R11 protein, human; D044767:Ubiquitin-Protein Ligases; D004398:Dyneins; D015739:Nocodazole