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Marisa Otegui

Assistant Professor of Botany

Marisa Otegui
Lab Home Page:
Otegui Lab
Address:
B119 Birge Hall
Telephone:
265-5703
Email:
otegui@wisc.edu
Research Fields:
Plant Genetics
Molecular Genetics
Arabidopsis

Ph.D., University of La Plata, Argentina, 1996

Postdoctoral Research: University of Colorado-Boulder

Research Interests

Protein trafficking in plantsProtein trafficking in plants

Research Description

We are interested in structural and functional aspects of multivesicular bodies (MVBs) in plant cells. MVBs are endosomes that consist of a limiting membrane and internal vesicles. The internal vesicles arise from invaginations of the limiting membrane and carry membrane proteins targeted for degradation in the lysosome/vacuole. MVBs play a crucial role in both the endocytic and the secretory pathways of all eukaryotic cells, sorting proteins for degradation or recycling, downregulating receptors, and mediating the transport of proteins to the vacuole/lysosome. Thus, MVB functions are tightly related to cell signaling, differentiation, and transport of vacuolar cargoes.

The endosomal invagination process is unique because, unlike most vesiculation processes characterized to date, the vesiculating membrane buds away from the cytoplasm. This invagination process requires the concentration of membrane proteins into specific membrane domains and the initiation of budding into the MVB lumen. Multisubunit protein complexes called endosomal sorting complexes required for transport I, II, and III (ESCRT-I, -II,-III) mediate membrane protein sorting into MVB internal vesicles. In plants, MVBs have been adapted to serve both the same functions as in yeast and mammalian cells as well as unique plant functions. In particular, plant MVBs appear to play a central role in the transport and processing of vacuolar storage proteins and recycling of membrane removed from the cell plate during cytokinesis. We are addressing questions such as: How many classes of endosomal compartments exist in plants? How do MVBs arise? What are their functions in different cell types? What is the molecular machinery responsible for MVB sorting and invagination?

We are interested in structural and functional aspects of multivesicular bodies (MVBs) in plant cells. MVBs are endosomes that consist of a limiting membrane and internal vesicles. The internal vesicles arise from invaginations of the limiting membrane and carry membrane proteins targeted for degradation in the lysosome/vacuole. MVBs play a crucial role in both the endocytic and the secretory pathways of all eukaryotic cells, sorting proteins for degradation or recycling, downregulating receptors, and mediating the transport of proteins to the vacuole/lysosome. Thus, MVB functions are tightly related to cell signaling, differentiation, and transport of vacuolar cargoes.

The endosomal invagination process is unique because, unlike most vesiculation processes characterized to date, the vesiculating membrane buds away from the cytoplasm. This invagination process requires the concentration of membrane proteins into specific membrane domains and the initiation of budding into the MVB lumen. Multisubunit protein complexes called endosomal sorting complexes required for transport I, II, and III (ESCRT-I, -II,-III) mediate membrane protein sorting into MVB internal vesicles. In plants, MVBs have been adapted to serve both the same functions as in yeast and mammalian cells as well as unique plant functions. In particular, plant MVBs appear to play a central role in the transport and processing of vacuolar storage proteins and recycling of membrane removed from the cell plate during cytokinesis. We are addressing questions such as: How many classes of endosomal compartments exist in plants? How do MVBs arise? What are their functions in different cell types? What is the molecular machinery responsible for MVB sorting and invagination?

Representative Publications

  • Spitzer, C., Reyes, F.C., Buono, R., Sliwinski, M.K., Haas, T.J., Otegui, M.S. 2009. The ESCRT-related CHMP1A and B proteins mediate multivesicular body sorting of auxin carriers and are required for plant development. The Plant Cell (in press). .
  • Ebine, K. Okatani, Y., Uemura, T., Goh, T., Shoda, K., Niihama, M., Terao Morita, M., Spitzer, C., Otegui, M.S., Nakano, A. and Ueda, T. 2008. A SNARE complex unique to seed plants is required for vacuole biogenesis and seed development of Arabidopsis thaliana. The Plant Cell 20: 3006-21.
  • Tian, Q., Olsen, L., Sun, B., Lid, S.E., Brown, R., Lemmon, B.E., Fosnes, K., Gruis, F., Opsahl-Sorteberg, H.-G., Otegui, M.S. and Olsen, O.-A. 2007. Subcellular localization and functional domain studies of DEFECTIVE KERNEL 1 in maize and Arabidopsis thaliana suggest a model for aleurone cell fate specification involving CRINKLY 4 and SUPERNUMERARY ALEURONE LAYER 1. The Plant Cell 19: 3127-3145.
  • Haas, T.J., Sliwinski, M.K., Mart'nez, D.E., Preuss, M., Ueda, T., Nielsen, E., Odorizzi, G., and Otegui, M.S. 2007. The Arabidopsis AAA ATPase SKD1 is involved in multivesicular endosome function and interacts with its positive regulator LIP5. The Plant Cell 19:1295-312.
  • Otegui, M.S., Herder, R., Schulze, J., Jung, R., Staehelin, L.A. 2006. The proteolytic processing of seed storage proteins in Arabidopsis embryo cells starts in the multivesicular bodies. The Plant Cell 18: 2567-2581.
  • Preuss, M.L., Schmitz, A.J., Thole, J.M. Bonner, H.K.S., Otegui, M.S., Nielsen, E. 2006. A role for the RabA4b effector protein, PI-4K?1, in polarized expansion of root hair cells in Arabidopsis. Journal Cell Biology 172:991-8.