Chemists at The University of Texas at Austin have discovered a key protein in how lysosomes, the cell’s recycling centers, work. Lysosomes are acidic, membrane-bound organelles that contain hydrolytic enzymes for the digestion of polymers and other macromolecules. They are essential for the homeostasis and survival of eukaryotic cells.

The protein, called LAMP-2A, is a member of the lysosome-associated membrane protein (LAMP) family. LAMPS are involved in various cellular processes, including lysosome biogenesis, membrane trafficking, and autophagy.

The researchers found that LAMP-2A is required for the proper fusion of lysosomes with autophagosomes, which are double-membrane vesicles that deliver cytoplasmic material to lysosomes for degradation. This fusion event is essential for the recycling of cellular components and the maintenance of cellular homeostasis.

“We were surprised to find that LAMP-2A is essential for autophagosome-lysosome fusion,” said Dr. Richard P. Apkarian, professor of chemistry at UT Austin and co-senior author of the study. “This finding challenges the current understanding of the molecular mechanisms of lysosomal function.”

The research team used a combination of biochemical and cell biological techniques to identify LAMP-2A as a key regulator of autophagosome-lysosome fusion. They found that LAMP-2A is present on both lysosomes and autophagosomes and that it interacts with other proteins involved in membrane fusion.

“Our findings provide new insights into the molecular mechanisms of lysosomal function and may have implications for understanding lysosomal storage diseases and other disorders associated with impaired autophagy,” said Dr. Jiangli Chen, research associate in the Apkarian lab and co-first author of the study.

The study was published in the journal Nature Communications.