Lysosome-associated membrane glycoprotein 1

LAMP1 (lysosome-associated membrane glycoprotein 1) is a 417-amino acid lysosomal membrane protein that functions as a critical regulator of lysosomal biology. It plays key roles in lysosome biogenesis, pH regulation, autophagy, and cholesterol homeostasis, partly through direct inhibition of the proton channel TMEM175 to facilitate lysosomal acidification (UniProt: P11279). The protein also contributes to natural killer cell cytotoxicity by regulating cytotoxic granule trafficking and protecting cells from degranulation-associated damage, and serves as a carbohydrate ligand presenter to selectins.

LAMP1 is highly expressed in lysosomes and is implicated in immune function and cellular homeostasis pathways. Beyond its canonical roles, it acts as a cellular receptor for Lassa virus and supports processing of mumps virus fusion proteins during microbial infection (UniProt: P11279).

In Alzheimer's Disease, LAMP1 shows disease-relevant upregulation. Human post-mortem AD brain tissue exhibits increased LAMP1 protein levels compared to age-matched controls (mean log2FC = 0.99) as measured by TMT-labeled quantitative proteomics across subcellular fractions (Chaparral AD proteomics). This upregulation may reflect compensatory lysosomal dysfunction or altered autophagy-related pathways characteristic of AD neurodegeneration.