Identification of vesicle components involved in apical protein transport
Prof. Dr. Ralf Jacob
Institut für Klinische Zytobiologie und Zytopathologie
Phone: +49 6421 286 6482
Fax: +49 6421 286 6414
Polarized epithelial cells contain a plasma membrane that is divided into two separate compartments, an apical and a basolateral compartment. Each membrane compartment is composed of distinct proteins and lipids, which are sorted by specific sorting mechanisms into the correct membrane domain. At least two different transport pathways can provide the apical membrane with newly synthesized material. Compartments that are traversed by these pathways as well as the implicated protein- and lipid-components will be analysed.
Different models for apical protein sorting. Two scenarios for apical protein sorting are represented in this figure. In the classical scenario raft-associated (red) and non-associated material is sorted in the TGN into apical vesicle populations (II). The new scenario describes the transport of raft-associated and non-associated cargo to common recycling endosomes (CRE). This compartment segregates apical material into distinct vesicle populations (LAVs and SAVs).
1. Detection of transport routes involved in apical protein trafficking.
• In which subapical compartments is apical cargo sorted into distinct vesicles and do these compartments also contain basolateral cargo molecules? How is the dynamics of protein trafficking at the apical cell surface?
- use state of the art microscopic techniques like apical TIRF- or high resolution microscopy in combination with a repertoire of fluorescent fusion proteins in living cells
2. Identification of vesicle-associated protein components.
• How is the composition of apical transport vesicles and how does this change on the passage to the cell surface?
- analyse immunoisolated apical transport vesicles by 2D-SDS-PAGE and mass spectrometry
3. Unraveling the role of lipids in apical protein transport.
• Where and when are lipids sorted after TGN-release? Which lipids/ lipid classes are found in apical transport vesicle populations?
- analysis of representative fluorescently labelled cholesterol-, sphingolipid- and phospholipid-variants by fluorescence microscopy as well as quantitative fluorescence detection to monitor their segregation into separate vesicle populations
Dr. Sabrina Zink, Postdoc
Martina Dienst, Technician
Dominik Schneider, PhD student
Tamara Straube, PhD student
Publications since 2007
D. Delacour, C. Greb, A. Koch, E. Salomonsson, H. Leffler, A. LeBivic und R. Jacob (2007):
Apical Sorting by Galectin-3 Dependent Glycoprotein Clustering.
Traffic, 8, 379-388
D. Delacour, A. Koch, W. Ackermann, I. Eude-Le Parco, H.-P. Elsässer, F. Poirier und R. Jacob (2008):
Loss of galectin-3 impairs membrane polarisation of mouse enterocytes in vivo.
The Journal of Cell Science, 121, 458-465
C.I. Cramm-Behrens, M. Dienst und R. Jacob (2008):
Apical cargo traverses endosomal compartments on the passage to the cell surface.
Traffic, 9, 2206-2220
D. Delacour, A. Koch und R. Jacob (2009):
The role of galectins in protein trafficking.
Traffic, 10, 1405-1413
A. Koch, F. Poirier, R. Jacob und D. Delacour (2010):
Galectin-3, a novel centrosome-associated protein, required for epithelial morphogenesis.
K. Astanina und R. Jacob (2010):
KIF5C, a kinesin motor involved in apical trafficking of MDCK cells.
Cellular and Molecular Life Sciences, 67, 1331-1342
D. Schneider, C. Greb, A. Koch, T. Straube, A. Elli, D. Delacour und R. Jacob (2010):
Trafficking of galectin-3 through endosomal organelles of polarized and non-polarized cells
European Journal of Cell Biology, 89, 788-798
K. Astanina, C.I. Delebinski, D. Delacour und R. Jacob (2010):
Annexin XIIIb guides raft-dependent and –independent apical traffic in MDCK cells
European Journal of Cell Biology, 89, 799-806
50. K. Vormund, N.A. Bonekamp, R. Jacob und M. Schrader (2010):
Dynamin-like protein 1 at the Golgi complex: A novel component of the sorting/targeting machinery en route to the plasma membrane.
Experimental Cell Research, 316, 3454-3467