Physicochemical Properties of α-Taxilin as a Putative Tethering Factor

抄録

α-Taxilin is a member of the taxilin family, a binding partner of the syntaxin family involved in intracellular vesicle traffic. The taxilin family members share a long coiled-coil structure, which is homologous to that of Uso1, a yeast homologue of p115. It has been revealed that a parallel homodimerization of p115, an elongated polypeptide, is required for tethering of the transport vesicles to the acceptor membrane. In this study we examined whether α-taxilin has similar biochemical properties to p115. Gel filtration and sedimentation analyses suggest that α-taxilin is an elongated polypeptide containing a long coiled-coil structure. A pull-down assay revealed that His₆-α-taxilin binds to GST-α-taxilin, and not to GST in dose-dependent and saturable manners. α-Taxilin formed a parallel homodimer through at least two independent regions. Together, α-taxilin may be involved in tethering of the transport vesicles to the acceptor membranes in a similar way to p115.