Required for correct export to the cell surface of some cell outer membrane lipoproteins both in Neisseria and heterologously in E.coli. Interacts with the C-terminal domain of surface lipoprotein TbpB. Consists of a soluble N-terminal domain and C-terminal probable beta-barrel in the outer membrane with 14 predicted beta-strands (Probable). Expression of just the C-terminal domain restores about 30% levels of TbpB lipoprotein and nearly 100% levels of fHbp lipoprotein on the cell surface in strains B16B6 and MC58, and confers surface expression of lipoproteins TbpB, LbpB and fHbp, but not HpuA in E.coli (PubMed:27572441). Does not surface present lipoproteins TbpB, LbpB or fHbp (in strains B16B6 and MC58). Bacteria are considerably less virulent in mouse sepsis model (shown in strain B16B6 only). Present in outer membrane vesicle formulations which are used as vaccines in human. Belongs to the Slam family.