Identification of a novel light intermediate chain (D2LIC) for mammalian cytoplasmic dynein 2.
The diversity of dynein's functions in mammalian cells is a manifestation of both the existence of multiple dynein heavy chain isoforms and an extensive set of associated protein subunits. In this study, we have identified and characterized a novel subunit of the mammalian cytoplasmic dynein 2 complex. The sequence similarity between this 33-kDa subunit and the light intermediate chains (LICs) of cytoplasmic dynein 1 suggests that this protein is a dynein 2 LIC (D2LIC). D2LIC contains a P-loop motif near its NH(2) terminus, and it shares a short region of similarity to the yeast GTPases Spg1p and Tem1p. The D2LIC subunit interacts specifically with DHC2 (or cDhc1b) in both reciprocal immunoprecipitations and sedimentation assays. The expression of D2LIC also mirrors that of DHC2 in a variety of tissues. D2LIC colocalizes with DHC2 at the Golgi apparatus throughout the cell cycle. On brefeldin A-induced Golgi fragmentation, a fraction of D2LIC redistributes to the cytoplasm, leaving behind a subset of D2LIC that is localized around the centrosome. Our results suggest that D2LIC is a bona fide subunit of cytoplasmic dynein 2 that may play a role in maintaining Golgi organization by binding cytoplasmic dynein 2 to its Golgi-associated cargo.
Grissom
Paula M
PM
Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, Colorado 80309-0347, USA. grissom@Colorado.edu
Vaisberg
Eugeni A
EA
McIntosh
J Richard
JR
D000595:Amino Acid Sequence; D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology; D001483:Base Sequence; D020126:Brefeldin A / Q000494:pharmacology; D019556:COS Cells; D002460:Cell Line; D004398:Dyneins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D006056:Golgi Apparatus / Q000378:metabolism*; D006801:Humans; D007527:Isoenzymes; D037241:Mannose-Binding Lectins / Q000378:metabolism; D008565:Membrane Proteins / Q000378:metabolism; D051379:Mice; D008969:Molecular Sequence Data; D015739:Nocodazole / Q000494:pharmacology; D021122:Protein Subunits; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D016415:Sequence Alignment; D014018:Tissue Distribution; D014404:Tubulin / Q000378:metabolism
D000970:Antineoplastic Agents; D007527:Isoenzymes; C084004:LMAN1 protein, human; D037241:Mannose-Binding Lectins; D008565:Membrane Proteins; D021122:Protein Subunits; D011500:Protein Synthesis Inhibitors; D011993:Recombinant Fusion Proteins; D014404:Tubulin; D020126:Brefeldin A; D004398:Dyneins; D015739:Nocodazole