Reference - Detail
|Author||Kita A, Li C, Yu Y, Umeda N, Doi A, Yasuda M, Ishiwata S, Taga A, Horiuchi Y, Sugiura R.|
|Title||Role of the Small GTPase Rho3 in Golgi/Endosome trafficking through functional interaction with adaptin in Fission Yeast.|
BACKGROUND:We had previously identified the mutant allele of apm1(+) that encodes a homolog of the mammalian µ1A subunit of the clathrin-associated adaptor protein-1 (AP-1) complex, and we demonstrated the role of Apm1 in Golgi/endosome trafficking, secretion, and vacuole fusion in fission yeast.
METHODOLOGY/PRINCIPAL FINDINGS:In the present study, we isolated rho3(+), which encodes a Rho-family small GTPase, an important regulator of exocystosis, as a multicopy-suppressor of the temperature-sensitive growth of the apm1-1 mutant cells. Overexpression of Rho3 suppressed the Cl(-) sensitivity and immunosuppressant sensitivity of the apm1-1 mutant cells. Overexpression of Rho3 also suppressed the fragmentation of vacuoles, and the accumulation of v-SNARE Syb1 in Golgi/endosomes and partially suppressed the defective secretion associated with apm1-deletion cells. Notably, electron microscopic observation of the rho3-deletion cells revealed the accumulation of abnormal Golgi-like structures, vacuole fragmentation, and accumulation of secretory vesicles; these phenotypes were very similar to those of the apm1-deletion cells. Furthermore, the rho3-deletion cells and apm1-deletion cells showed very similar phenotypic characteristics, including the sensitivity to the immunosuppressant FK506, the cell wall-damaging agent micafungin, Cl(-), and valproic acid. Green fluorescent protein (GFP)-Rho3 was localized at Golgi/endosomes as well as the plasma membrane and division site. Finally, Rho3 was shown to form a complex with Apm1 as well as with other subunits of the clathrin-associated AP-1 complex in a GTP- and effector domain-dependent manner.
CONCLUSIONS/SIGNIFICANCE:Taken together, our findings reveal a novel role of Rho3 in the regulation of Golgi/endosome trafficking and suggest that clathrin-associated adaptor protein-1 and Rho3 co-ordinate in intracellular transport in fission yeast. To the best of our knowledge, this study provides the first evidence of a direct link between the small GTPase Rho and the clathrin-associated adaptor protein-1 in membrane trafficking.
|MeSH||Adaptor Protein Complex 1 / genetics Adaptor Protein Complex 1 / metabolism* Adaptor Protein Complex mu Subunits / genetics Adaptor Protein Complex mu Subunits / metabolism* Amino Acid Sequence Biological Transport / genetics Endosomes / genetics Endosomes / metabolism* Golgi Apparatus / genetics Golgi Apparatus / metabolism* Molecular Sequence Data Organisms, Genetically Modified Protein Binding Schizosaccharomyces / enzymology Schizosaccharomyces / genetics* Schizosaccharomyces / metabolism* Schizosaccharomyces pombe Proteins / genetics Schizosaccharomyces pombe Proteins / metabolism* Schizosaccharomyces pombe Proteins / physiology* rho GTP-Binding Proteins / genetics rho GTP-Binding Proteins / metabolism* rho GTP-Binding Proteins / physiology*|
|WOS Category||CELL BIOLOGY|
|Yeast||Genome DNA clones|