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DNM1, a dynamin-related gene, participates in endosomal trafficking in yeast.

ABSTRACT: We identified DNM1, a novel dynamin-related gene in Saccharomyces cerevisiae. Molecular and genetic mapping showed that DNM1 is the most proximal gene to the right of centromere 12, and is predicted to encode a protein of 85 kD, designated Dnm1p. The protein exhibits 41% overall identity with full-length dynamin I and 55% identity with the most highly conserved 400-amino acid GTPase region. Our findings show that like mammalian dynamin, Dnm1p participates in endocytosis; however, it is unlikely to be a cognate homologue. Cells with a disruption in the DNM1 gene showed mating response defects consistent with a delay in receptor-mediated endocytosis. The half-life of the Ste3p pheromone receptor was increased two- to threefold in the dnm1 mutant, demonstrating that Dnm1p participates in the constitutive turnover of the receptor. To define the step in the endocytic pathway at which Dnm1p acts, we analyzed mutant strains at both early and late steps of the process. Initial internalization of epitope-tagged pheromone receptor or of labeled pheromone proceeded with wild-type kinetics. However, delivery of the internalized receptor to the vacuole was greatly impeded during ligand-induced endocytosis. These data suggest that during receptor-mediated endocytosis, Dnm1p acts after internalization, but before fusion with the vacuole. The dnm1 mutant was not defective for sorting of vacuolar proteins, indicating that Dnm1p is not required for transport from the late endosome to the vacuole. Therefore, we suggest that Dnm1p participates at a novel step before fusion with the late endosome.

SUBMITTER: Gammie AE

PROVIDER: S-EPMC2120539 | biostudies-other | 1995 Aug

REPOSITORIES: biostudies-other

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DNM1, a dynamin-related gene, participates in endosomal trafficking in yeast.

Gammie A E AE Kurihara L J LJ Vallee R B RB Rose M D MD

The Journal of cell biology 19950801 3

We identified DNM1, a novel dynamin-related gene in Saccharomyces cerevisiae. Molecular and genetic mapping showed that DNM1 is the most proximal gene to the right of centromere 12, and is predicted to encode a protein of 85 kD, designated Dnm1p. The protein exhibits 41% overall identity with full-length dynamin I and 55% identity with the most highly conserved 400-amino acid GTPase region. Our findings show that like mammalian dynamin, Dnm1p participates in endocytosis; however, it is unlikely ...[more]

PMID: 7622557

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Project description:High-density oligonucleotide microarrays were used to compare gene expression profiles from uncultured CD34+/CD38lo cells and culture-derived megakaryocytes (MKs). As previously published, three replicate microarray data sets from three different sources of organ donor marrow were analyzed using the software program Rosetta Resolver. After setting a stringent p value of <or=0.001 with a fold change cutoff of three or more in expression level, dynamin 3 (DNM3) was identified to be differentially expressed during the course of MK development with a mean fold-change of 8.2+/-2.1 (mean+/-standard deviation). DNM3 is a member of a family of mechanochemical enzymes (DNM1, DNM2, and DNM3) known for their participation in membrane dynamics by hydrolyzing nucleotides to link cellular membranes to the actin cytoskeleton. Real-time quantitative polymerase chain reaction confirmed that DNM3 increased by 20.7-+/-3.4-fold (n=4, p=0.09) during megakaryocytopoiesis and Western blot analysis showed that DNM3 protein was expressed in human MKs. Confocal microscopy revealed that DNM3 was distributed diffusely throughout the cytoplasm of MKs with a punctate appearance in proplatelet processes. Immunogold electron microscopy also showed that DNM3 is widely distributed in the cytoplasm of MKs, with no apparent localization to specific organelles. The open reading frame of DNM3 was cloned from culture-derived human MKs and determined to be 100% identical to the protein encoded by the DNM3 transcript variant ENST00000367731 published in the Ensemble database. Overexpression of DNM3 in umbilical cord blood CD34+ cells resulted in an increase in total nucleated cells, an amplification of total colony-forming cells and colony-forming unit-megakaryocytes, and a concomitant increase in the expression of nuclear factor erythroid 2 (NF-E2) and beta-tubulin. Together these findings provide the first evidence that a member of the dynamin family of mechanochemical enzymes is present in human MKs and indicate that DNM3 is an excellent candidate for playing an important role in mediating cytoskeleton and membrane changes that occur during MK/platelet development.

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DNM1, a dynamin-related gene, participates in endosomal trafficking in yeast.

Publications

DNM1, a dynamin-related gene, participates in endosomal trafficking in yeast.

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