The gene expression control properties of many different pairs of connectrons are described in terms of the similarity or disparity of the connectron sources and the symmetry or asymmetry of the resulting pairs of connectrons. It is based, at least in part, on the discovery of tethering molecules which may be used to non-covalently link antigenic peptides to heat shock proteins. A slanted triangular support surface having number of hooks and pockets provide convenient attachment points and storage spaces for bags and packages. Tabs extending from the supports limit the sliding movement of the storage basket.