Our research is focused on the biogenesis of the Golgi apparatus in mammalian cells. In particular, we are interested in the regulation of the growth and division of the Golgi apparatus. During the cell cycle the single copy of the Golgi apparatus has to grow in interphase and then be equally divided into the two daughter cells during cell division. At the onset of mitosis the Golgi complex breaks down into vesicles, which are partitioned equally between the two daughter cells where they subsequently fuse to form a new Golgi apparatus.
We could show that treatments such as Brefeldin A (BFA) that interfere with vesicle transport between the endoplasmic reticulum (ER) and the Golgi complex induce redistribution of Golgi enzymes into the ER, leaving behind a matrix of Golgi structural proteins and remnant vesicles. This enzyme-depleted Golgi matrix can form and maintain the higher order structure that resembles the intact organelle. Furthermore, the matrix is partitioned normally between daughter cells during mitosis suggesting that it can constitute the Golgi apparatus proper, responsible for its growth and division. Our focus is to characterize this process and the proteins that make up the Golgi matrix in order to understand its role in determining the structure of the Golgi apparatus and its biogenesis.
RESEARCH INTERESTS
Biogenesis of the Golgi apparatus
Mitosis
Membrane traffic
Cholesterol
RECENT PUBLICATIONS
Bartz R, Sun LP, Bisel B, Wei JH, Seemann J, "Spatial separation of Golgi and ER during mitosis protects SREBP from unregulated activation" EMBO J., 27:948-955, 2008
Wang Y, Wei JH, Bisel B, Seemann J, "Golgi cisternal unstacking stimulates COPI vesicle budding and protein transport" PLoS ONE, 3:e1647, 2008
Bartz R, Seemann J, "Mitotic regulation of SREBP and ATF6 by separation of the Golgi and ER" Cell Cycle, vol.7 issue14, July 2008
Sun LP, Seemann J, Goldstein JL, Brown MS, "Oxysterol-Insig complex renders sorting signal in Scap inaccessible to COPII proteins" PNAS, 104:6519, 2007
Xiang Y, Seemann J, Bissel B, Punthambaker S, Wang Y, "Active ARF is required for mitotic Golgi fragmentation" J. Biol. Chem., 282:21829, 2007
SIGNIFICANT PUBLICATIONS
Seemann J, Pypaert M, Taguchi T, Malsam J, Warren G, "Partitioning of the matrix fraction of the Golgi apparatus during mitosis in animal cells" Science, 295:848, 2002
Seemann J, Jokitalo E, Pypaert M, Warren G, "Matrix proteins can generate the higher order architecture of the Golgi apparatus" Nature, 407:1022, 2000
Wang* Y, Seemann* J, Pypaert M, Shorter J, Warren G, "A direct role for GRASP65 as a mitotically regulated Golgi stacking factor" EMBO J., 22:3279, 2003
Seemann J, Jokitalo E, Warren G, "The role of the tethering proteins p115 and GM130 in transport through the Golgi apparatus in vivo" Mol. Biol. Cell, 11:635, 2000
Bartz R, Seemann J, Zehmer JK, Serrero G, Chapman KD, Anderson RGW, Liu P, "Mono-ADP-ribosylation of CtBP1/BARS regulates lipid storage" Mol. Biol. Cell, 18:3015, 2007
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