lysosomeassociated

Lysosome-associated is a term used in cell biology to describe molecules, proteins, or cellular processes that are localized to, interact with, or regulate lysosomes. Lysosomes are membrane-bound organelles containing hydrolytic enzymes that operate at an acidic pH to degrade macromolecules, playing a central role in cellular recycling, metabolism, and homeostasis.

A major group of lysosome-associated proteins are the lysosome-associated membrane glycoproteins (LAMPs). The best known members are LAMP1 and LAMP2, which populate most lysosomal membranes and are heavily glycosylated. They contribute to lysosome integrity, regulate membrane trafficking, and participate in autophagy and endocytosis. LAMP2 has several isoforms generated by alternative splicing; LAMP2A acts as a receptor for chaperone-mediated autophagy (CMA), a selective degradation pathway in which cytosolic proteins are delivered to lysosomes for translocation and breakdown. LAMP2B and LAMP2C have distinct or less well-defined roles.

A related protein is LAMP3, also called DC-LAMP, which is expressed in dendritic cells and some cancers and is associated with antigen processing and dendritic cell maturation. Additional lysosome-associated components include the v-ATPase complex that acidifies the lysosome and various membrane fusion proteins that mediate lysosome trafficking and autophagic flux.

Clinical and research relevance: defects or altered expression of lysosome-associated proteins can contribute to diseases such as Danon disease (LAMP2 mutations) and age-related or neurodegenerative disorders where CMA and lysosome function are compromised. LAMP1 and LAMP2 are commonly used as lysosomal markers in experiments studying lysosome biology.