Plays an important role in chaperone-mediated autophagy, a process that mediates lysosomal degradation of proteins in response to various stresses and as part of the normal turnover of proteins with a long biological half-live (PubMed:8662539, PubMed:11082038, PubMed:18644871, PubMed:24880125, PubMed:27628032). Functions by binding target proteins, such as GAPDH and MLLT11, and targeting them for lysosomal degradation (PubMed:8662539, PubMed:11082038, PubMed:18644871, PubMed:24880125). Plays a role in lysosomal protein degradation in response to starvation (By similarity). Required for the fusion of autophagosomes with lysosomes during autophagy (PubMed:27628032). Cells that lack LAMP2 express normal levels of VAMP8, but fail to accumulate STX17 on autophagosomes, which is the most likely explanation for the lack of fusion between autophagosomes and lysosomes (PubMed:27628032). Required for normal degradation of the contents of autophagosomes (PubMed:27628032). Required for efficient MHCII-mediated presentation of exogenous antigens via its function in lysosomal protein degradation; antigenic peptides generated by proteases in the endosomal/lysosomal compartment are captured by nascent MHCII subunits (PubMed:20518820). Is not required for efficient MHCII-mediated presentation of endogenous antigens (PubMed:20518820). Modulates chaperone-mediated autophagy. Decreases presentation of endogenous antigens by MHCII. Does not play a role in the presentation of exogenous and membrane-derived antigens by MHCII. (Microbial infection) Supports the FURIN-mediated cleavage of mumps virus fusion protein F by interacting with both FURIN and the unprocessed form but not the processed form of the viral protein F. Monomer (PubMed:18644871, PubMed:25342746). Homodimer (PubMed:25342746). Homotrimer (PubMed:25342746). Forms large homooligomers (PubMed:18644871). Interacts (via its cytoplasmic region) with HSPA8 (PubMed:25342746). Interacts with HSP90 in the lysosome lumen; this enhances LAMP2 stability (By similarity). Interacts with MLLT11 (PubMed:24880125). Interacts with ABCB9 (PubMed:22641697). Interacts with FURIN (PubMed:32295904). (Microbial infection) Interacts with mumps virus protein F; this interaction promotes protein F cleavage by FURIN. This protein shuttles between lysosomes, endosomes, and the plasma membrane. Isoform LAMP-2A is highly expressed in placenta, lung and liver, less in kidney and pancreas, low in brain and skeletal muscle (PubMed:7488019, PubMed:26856698). Isoform LAMP-2B is detected in spleen, thymus, prostate, testis, small intestine, colon, skeletal muscle, brain, placenta, lung, kidney, ovary and pancreas and liver (PubMed:7488019, PubMed:26856698). Isoform LAMP-2C is detected in small intestine, colon, heart, brain, skeletal muscle, and at lower levels in kidney and placenta (PubMed:26856698). In peripheral blood B cells isoform LAMP-2A, LAMP-2B and LAMP-2C are up-regulated in response to treatments that stimulate immune responses via the Toll-like receptors TLR7 or TLR9. O- and N-glycosylated; some of the 16 N-linked glycans are polylactosaminoglycans. The disease is caused by variants affecting the gene represented in this entry. Belongs to the LAMP family.