Vesicular transport in eukaryotic cells depends on conserved sets of proteins involved in the sequential steps of vesicle budding, uncoating, and tethering to the target membrane, as well as in membrane fusion and cargo release. Vesicle tethering at the target membrane is regulated by Rab/Ypt GTPases and involves both heteromultimeric tethering complexes and factors characterized by extended coiled-coil regions. We have extended earlier studies of the transport protein particle (TRAPP), a factor required for ER-to-Golgi transport by elucidating the crystal structure of the TRAPP-associated protein Tca17. For the golgin p115, whose crystal structure was determined earlier, we could eliminate a confusion as to the nature of the repeats forming the protein structure by proving unequivocally that p115 is made up of armadillo repeats and not of a new kind of repeats typical for tethering protein (Figure).
Figure adapted from
Striegl, H., Andrade-Navarro, M.A., Heinemann, U.
PLoS ONE 5 (2): e8991 (2010-02)