Mediates the entry of L.monocytogenes into host intestinal epithelial cells; transformation with inlA alone allows L.innocua (a non-invasive species) to be taken up by host cells (PubMed:1905979, PubMed:8601315, PubMed:10406800). Binds to human receptor cadherin-1 (E-cadherin, CDH1); the chicken homolog of cadherin-1 but not cadherin-2 function as receptors (PubMed:8601315). Mouse cadherin-1 is not a receptor, however mutating a single surface-exposed residue (Glu-172 to Pro in mouse) allows cadherin-1 to act as a receptor for InlA (PubMed:10406800). Bacterial uptake is inhibited by EDTA and by anti-E-cadherin antibodies. Interacts with host (human) cadherin-1 (CDH1) (PubMed:12526809, PubMed:17540170, PubMed:17715295). The formation of the complex between inlA and cadherin-1 is calcium-dependent (PubMed:12526809). Mutagenesis studies show it is possible to increase the affinity of InlA for CDH1 by rational engineering of InlA residues (PubMed:17715295). In the absence of SrtA in exponential phase some protein is still anchored to the cell wall and a very small amount is secreted while overall protein levels are the same in the srtA mutant; in stationary phase almost no protein accumulates (PubMed:22837151). During exponential growth detected on the cell surface as a series of dots in a helical pattern, it is excluded from the septum; if expression is increased it accumulates at cell poles (PubMed:21725001). The helical pattern of InlA does not overlap with that of InlH, InlJ or Hbp2 (SvpA) (PubMed:21725001). In stationary phase colocalizes with InlH at cell poles and at the septum, the location shift requires SigB (PubMed:21725001). More prevalent in stationary than exponential phase (at protein level) (PubMed:16247833, PubMed:21725001). Levels maybe post-transcriptionally decreased by InlH; disruption of inlH in some strains (EGD-e and EGD-2) leads to increased levels of InlA (at protein level) (PubMed:20176794). Consists of an N-terminal cap, a leucine-rich repeat domain (LRR), and an Ig-like interrepeat domain. Deletion of both inlA and inlB prevents bacterial uptake by human enterocyte-like cell line Caco-2 (PubMed:1905979). Deletion of inlA alone decreases host cell entry; the reduction varies from 98% to none depending on the cell line tested (PubMed:11929538, PubMed:8601315, PubMed:10406800). Belongs to the internalin family.