The OS-9 gene maps to a region (q13-15) of chromosome 12 that is highly amplified in human osteosarcomas and encodes a protein of unknown function. Here we have characterized a homolog designated as YOS9 (YDR057w) from Saccharomyces cerevisiae. The yeast protein (Yos9) is a membrane-associated glycoprotein that localizes to the endoplasmic reticulum (ER). YOS9 interacts genetically with genes involved in ER-Golgi transport, particularly SEC34, whose temperature-sensitive mutant is rescued by YOS9 overexpression. Interestingly, Yos9 appears to play a direct role in the transport of glycosylphosphatidylinositol (GPI)-anchored proteins to the Golgi apparatus. Yos9 binds directly to Gas1 and Mkc7 and accelerates Gas1 transport and processing in cells overexpressing YOS9. Correspondingly, Gas1 processing is slowed in cells bearing a deletion in YOS9. No effect upon the transport and processing of non-GPI-anchored proteins (e.g. invertase and carboxypeptidase Y) was detected in cells either lacking or overexpressing Yos9. As Yos9 is not a component of the Emp24 complex, it may act as a novel escort factor for GPI-anchored proteins in ER-Golgi transport in yeast and possibly in mammals.
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http://dx.doi.org/10.1074/jbc.M201044200 | DOI Listing |
Mol Biol Cell
January 2025
Department of Molecular Genetics, The Ohio State University, Columbus, OH 43210.
The Munc13/UNC-13 family protein Ync13 is essential for septum integrity and cytokinesis in fission yeast. To further explore the mechanism of Ync13 functions, spontaneous suppressors of mutants, which can suppress the colony-formation defects and lysis phenotype of mutant cells, are isolated and characterized. One of the suppressor mutants, -, shows defects in the cytokinetic contractile ring constriction, septation, and daughter-cell separation, similar to mutant.
View Article and Find Full Text PDFJ Exp Bot
January 2025
Vegetable and Fruit Improvement Center and Department of Horticultural Sciences Texas A&M University, College Station, TX 77843, USA.
Complex N-glycans are asparagine (N)-linked branched sugar chains attached to secretory proteins in eukaryotes. They are produced by modification of N-linked oligosaccharide structures in the endoplasmic reticulum (ER) and Golgi apparatus. Complex N-glycans formed in the Golgi apparatus are often assigned specific roles unique to the host organism, with their roles in plants remaining largely unknown.
View Article and Find Full Text PDFCell Mol Life Sci
January 2025
Univ. Lille, CNRS, UMR 8576 - UGSF - Unité de Glycobiologie Structurale Et Fonctionnelle, 59000, Lille, France.
Glycans are known to be fundamental for many cellular and physiological functions. Congenital disorders of glycosylation (CDG) currently encompassing over 160 subtypes, are characterized by glycan synthesis and/or processing defects. Despite the increasing number of CDG patients, therapeutic options remain very limited as our knowledge on glycan synthesis is fragmented.
View Article and Find Full Text PDFNat Commun
December 2024
Shenzhen Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, China.
Iron is a potent biochemical, and accurate homeostatic control is orchestrated by a network of interacting players at multiple levels. Although our understanding of organismal iron homeostasis has advanced, intracellular iron homeostasis is poorly understood, including coordination between organelles and iron export into the ER/Golgi. Here, we show that SLC39A13 (ZIP13), previously identified as a zinc transporter, promotes intracellular iron transport and reduces intracellular iron levels.
View Article and Find Full Text PDFJ Transl Med
December 2024
Division of Hematology/Medical Oncology, Department of Medicine, Taichung Veterans General Hospital, No. 1650 Taiwan Boulevard, Sect. 4, Taichung, 407219, Taiwan.
Background: Bortezomib is a standard treatment for multiple myeloma (MM), working by the accumulation of toxic misfolded proteins in cancer cells. However, a significant clinical challenge arises from the development of resistance to bortezomib in MM treatment. Aggresome, a subcellular structure enclosed within Vimentin, forms in response to proteasome inhibitors and sequesters misfolded proteins that are transported by histone deacetylase 6 (HDAC6) and Dynein for degradation via autophagy, thereby reducing bortezomib's cytotoxic effects.
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