Plays an essential role in lymphocyte development by negatively regulating the canonical Wnt signaling pathway (PubMed:31073040). In association with UBAC2 and E3 ubiquitin-protein ligase AMFR, promotes the ubiquitin-mediated degradation of CTNNB1 and Wnt receptors FZD6 and LRP6 (PubMed:31073040). LMBR1L stabilizes the beta-catenin destruction complex that is required for regulating CTNNB1 levels (PubMed:31073040). Acts as a LCN1 receptor and can mediate its endocytosis (By similarity). Dimer (By similarity). Can also form higher oligomers (By similarity). Interacts with LCN1; this interaction mediates the endocytosis of LCN1 (By similarity). Interacts with UBAC2, FAF2, VCP, AMFR, ZNRF3, CTNNB1, LRP6, GSK3B, FZD6, DVL2 and RNF43 (PubMed:31073040). Interacts with GSK3A (By similarity). Interaction with LGB and SCGB1A1 is controversial (By similarity). Highly expressed in the bone marrow, thymus, spleen and lymphocytes. Mice exhibit severely impaired development of all lymphoid lineages, compromised antibody responses to immunization, reduced cytotoxic T-cell killing activity and natural killer (NK) cell function, and resistance to cytomegalovirus infection (PubMed:31073040). T-cells are predisposed to apoptosis and die in response to antigen-specific or homeostatic expansion signals (PubMed:31073040). Impaired differentiation of hematopoietic stem cells into the lymphoid primed multipotent progenitor (LMPP) and common lymphoid progenitor populations that give rise to T-cells, B-cells, and NK cells (PubMed:31073040). Belongs to the LIMR family.