Component of the Dot/Icm type IVB secretion system (T4BSS), which is used to inject bacterial effector proteins into eukaryotic host cells (PubMed:17040490, PubMed:22694730, PubMed:32513920). Part of a subcomplex which recruits effector proteins and delivers them to the core transmembrane subcomplex (PubMed:32513920). Forms the interacting surface for recruitment of acidic Glu-rich motif-containing effectors (PubMed:29410427). The T4BSS is a complex nanomachine composed of several subcomplexes. This subunit is part of the Type IV Coupling Complex (T4CC), a subcomplex composed of the DotLMNYZ core and the IcmSW-LvgA adapter subunits, linked by the C-terminal tail of DotL (PubMed:17040490, PubMed:22694730, PubMed:28714967, PubMed:32513920). Six DotLMNYZ hetero-pentameric units may assemble into an hexameric nanomachine, forming an inner membrane channel for effectors to pass through (PubMed:32513920). Interacts directly with DotL (PubMed:22694730, PubMed:32513920). Localizes to the poles of the cell. Exhibits patches of positively charged residues, which form binding sites for acidic Glu-rich peptides.