Acts as an adapter for the receptor ERBB2, in epithelia. By binding the unphosphorylated 'Tyr-1248' of receptor ERBB2, it may contribute to stabilize this unphosphorylated state (PubMed:16203728). Inhibits NOD2-dependent NF-kappa-B signaling and pro-inflammatory cytokine secretion (PubMed:16203728). Interacts with ERBB2, BPAG1 and ITGB4 (PubMed:10878805, PubMed:11375975, PubMed:12444095). May favor the localization of ERBB2, by restricting its presence to the basolateral membrane of epithelial cells. Also found to interact with ARVCF and delta catenin (PubMed:11821434). Interacts (via C-terminus) with DST Isoform 3 (via N-terminus) (PubMed:11375975). Interacts with NOD2 (via CARD domain) (PubMed:16203728). Found in hemidesmosomes, which are cell-substrate adhesion complexes in stratified epithelia. In transfected cells, either diffusely distributed over the cytoplasm or concentrated at the basolateral membrane. Colocalizes with the adrenergic receptors, ADREN1A and ADREN1B, at the nuclear membrane of cardiac myocytes (By similarity). Highly expressed in brain, heart, kidney, muscle and stomach, followed by liver, spleen and intestine. Belongs to the LAP (LRR and PDZ) protein family. Contaminating sequence. Potential poly-A sequence. Truncated N-terminus.