Expression,sorting, and segregation of Golgi proteins during germ cell differentiation in the testis |
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| Authors: | Catherine E Au Louis Hermo Elliot Byrne Jeffrey Smirle Ali Fazel Paul H G Simon Robert E Kearney Pamela H Cameron Charles E Smith Hojatollah Vali Julia Fernandez-Rodriguez Kewei Ma Tommy Nilsson John J M Bergeron |
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| Institution: | University of Michigan;aDepartment of Anatomy and Cell Biology, McGill University, Montreal, QC H3A 0C7, Canada;bDivision of Endocrinology and Metabolism, McGill University Health Centre Research Institute, Montreal, QC H3A 1A1, Canada;cDepartment of Biomedical Engineering Department, McGill University, Montreal, QC H3A 2B4, Canada;dCentre for Cellular Imaging, Sahlgrenska Academy, University of Gothenburg, 405 30 Gothenburg, Sweden |
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| Abstract: | The molecular basis of changes in structure, cellular location, and function of the Golgi apparatus during male germ cell differentiation is unknown. To deduce cognate Golgi proteins, we isolated germ cell Golgi fractions, and 1318 proteins were characterized, with 20 localized in situ. The most abundant protein, GL54D of unknown function, is characterized as a germ cell–specific Golgi-localized type II integral membrane glycoprotein. TM9SF3, also of unknown function, was revealed to be a universal Golgi marker for both somatic and germ cells. During acrosome formation, several Golgi proteins (GBF1, GPP34, GRASP55) localize to both the acrosome and Golgi, while GL54D, TM9SF3, and the Golgi trafficking protein TMED7/p27 are segregated from the acrosome. After acrosome formation, GL54D, TM9SF3, TMED4/p25, and TMED7/p27 continue to mark Golgi identity as it migrates away from the acrosome, while the others (GBF1, GPP34, GRASP55) remain in the acrosome and are progressively lost in later steps of differentiation. Cytoplasmic HSP70.2 and the endoplasmic reticulum luminal protein-folding enzyme PDILT are also Golgi recruited but only during acrosome formation. This resource identifies abundant Golgi proteins that are expressed differentially during mitosis, meiosis, and postacrosome Golgi migration, including the last step of differentiation. |
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