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:23028312, PubMed:32513920). Plays a central role in the assembly of the subcomplex (PubMed:32513920). Required for the recruitment of IcmS and IcmW to the inner membrane and for the translocation of adapter-dependent substrates (PubMed:23028312). May have ATPase activity (Probable). 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:23028312, PubMed:28714967, PubMed:32457311, 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 DotM (PubMed:22694730, PubMed:32513920). Interacts directly, via its C-terminal region, with the type IV adapter proteins IcmS and IcmW (PubMed:23028312, PubMed:28714967, PubMed:29203674, PubMed:32513920). Also interacts with DotN and LvgA via its C-terminal region (PubMed:28714967, PubMed:32513920). Localizes to the poles of the cell.