Lysosome Markers

Lysosomes are membrane-bound compartments responsible for the digestion and degradation of cellular components; a process called autophagy. Proton pumps within the lysosomal membrane create an acidic environment in the lumen providing optimal conditions for the activities of hydrolytic enzymes targeting proteins, lipids, nucleic acids, and carbohydrates. Considered the ‘recycling centre’ of the cell, lysosomes coordinate nutrient sensing and metabolism to regenerate biological monomers necessary for biosynthesis and energy production. Failure to regulate these processes disrupts cellular homeostasis, exacerbates cell damage events and accelerates ageing. Different pathways of lysosome-mediated autophagy can be utilised depending on the substrates being targeted for destruction. The major form of autophagy is called macro-autophagy. This requires the sequestration of damaged organelles and cytosolic proteins within a double-membraned organelle called an autophagosome. Maturation of autophagosomes and general activation of the macroautophagic pathway is prompted by dissociation of the mTORC1 signalling hub within the lysosome lumen. Next, autophagosome contents are delivered to the lysosome through a SNARE-dependent fusion event. This is facilitated by lysosomal integral membrane proteins LAMP1, LAMP2, LIMP2, as well as the tethering GTPase Rab7, and other factors including Beclin-1, ATG12, LC3B, and CD63. Post-fusion, the autolysosome is processed through degradation of the autophagosome inner membrane, reforming a continuous compartment whose contents will be digested. Other forms of autophagy include microautophagy and chaperone-mediated autophagy (CMA). While microautophagy involves the internalisation of cytosolic contents through lysosome membrane invagination, CMA is independent of vesicle formation, instead importing targeted proteins directly through a LAMP2A translocon complex embedded in the lysosomal membrane. Another critical role of lysosomes is borne out in the immune response by destroying invading pathogens. The lysosome surface receptor CD68 is central to this process of phagocytosis, explaining its use as key lysosomal marker in macrophage cells. These and many other membrane / protein trafficking events in lysosomal autophagy rely on complex signalling events controlling a vesicular transport network. For example, mannose-6-phosphate receptors (M6PRs) are required for trafficking hydrolytic enzymes from the Golgi towards lysosomes, while the small GTPase Rab9A is associated with the retrograde transport of recycled enzymes towards the Golgi within late endosomes. Overall, lysosomes are a vital organelle responsible for the degradation, recycling, and processing of various biological molecules. We offer a range of tracking dyes and antibodies, including CD34 antibodies, CD68 antibodies, LAMP1 antibodies, LAMP2 antibodies, and Myeloperoxidase antibodies, that can be used for studying these processes and furthering our understanding of basic science, disease progression and drug discovery. Our antibodies against lysosome-associated proteins cover various host species, isotypes, and conjugates and have been validated in multiple applications, ensuring lysosome function can be elucidated in an adaptable but robust manner.