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To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.cell.2005.11.016 Byline: Kai Simons (1), Carol Featherstone (2) Abstract: Basic research in Europe is about to receive a shot in the arm with the creation of a European Research Council (ERC). This new agency will sustain fundamental investigation into all aspects of scientific knowledge and should drive up standards of scientific research across the continent. Author Affiliation: (1) President, European Life Scientist Organization (ELSO); Director, Max Planck Institute for Cell Biology and Genetics, Dresden 01307, Germany (2) Coordinator, ELSO Career Development Committee, Fourquevaux 31450, France

All epithelial cells are characterized by specialized junctions, internal architecture and surface polarity which allow them to behave differently at their apical and basal sides. Epithelial cells have a polar cytoplasmic organization and a polar exterior and polarization is regulated by different mechanisms. The mechanism of polarization in four different epithelia is discussed.

Membrane transport of epithelial Madin-Darby canine kidney (MDCK) cells was inhibited by anti-N-ethylmaleimide-sensitive factor (NSF) in a permeabilized cell system, but was stimulated by alpha-soluble NSF attachment proteins. However, transport of cells from the trans-Golgi network to the apical cell surface was not affected by these proteins. Apical transport was also not affected by Rab-GDI and tetanus and botulinum neurotoxins which inhibit basolateral transport, suggesting that the Rab-NSF-SNAP-SNARE machinery only operates in basolateral transport.

The addition of N-glycan to proteins helps in protein folding and stabilizing of the protein structure after which the proteins can be transported out of the endoplasmic reticulum. N-glycan is also involved in the transfer of a GlcNAc phosphate to a mannose on the lysosome enzymes. However the proteins that do not undergo glycosylation or use a transport mechanism other than glycosylation have to use a sorting signal other than N-glycan. The transport of apical membrane proteins from the Golgi to the cell surface also involves N-glycan.

VIP 36 and ERGIC-53, two classes of animal lectins show remarkable similarity to leguminous plant lectins. ERGIC-53 shows resemblance to VIP36 in the region homologous to legume lectids. They influence the recycling of proteins and lipids and identify glycoprotein and glycolipid residues.