LAMP2, or lysosomal-associated membrane protein 2, is a well-recognized mediator of autolysosome (AL) maturation. It is involved in the autophagy-lysosomal protein degradation pathway, which is crucial for many cellular processes [1,5]. Mutations in the LAMP2 gene can lead to Danon disease, a rare X-linked dominant multisystemic disorder [2,5,6].

Genetic inactivation of Lamp2 in thymic stromal cells specifically impairs the development of CD4 T cells that completed positive selection, due to defects in autophagy in lamp2-deficient cortical thymic epithelial cells (cTECs) and alterations in MHC II processing, reducing CD4 TCR repertoire diversity [1]. In mice, Lamp2 deficiency also leads to age-dependent autofluorescence abnormalities of the fundus, thickening of Bruch's membrane, and the formation of basal laminar deposits similar to those in age-related macular degeneration (AMD), along with compromised lysosomal degradation and increased exocytosis in LAMP2-deficient retinal pigment epithelium (RPE) cells [7]. In addition, LAMP2 deficiency attenuates the neurodegeneration markers induced by HSV-1 infection, reducing viral DNA replication and tau hyperphosphorylation [3]. Engineered Aza-resistant MDS cell lines with LAMP2 deficiency show resistance to Azacytidine (Aza) and hypersensitivity to lysosome and autophagy inhibitors [4].

In conclusion, LAMP2 plays essential roles in autophagy-related cellular processes, T-cell development, and lysosomal function. Studies using Lamp2 knockout mouse models have revealed its significance in diseases such as Danon disease, AMD, neurodegeneration, and in determining drug response in MDS/AML. Understanding LAMP2 function provides insights into disease mechanisms and potential therapeutic targets.