Ups and downs of lysosomal pH: conflicting roles of LAMP proteins?

The acidic pH of lysosomes is critical for catabolism in eukaryotic cells and is altered in neurodegenerative disease including Alzheimer and Parkinson. Recent reports using Drosophila and mammalian cell culture systems have identified novel and, at first sight, conflicting roles for the lysosomal associated membrane proteins (LAMPs) in the regulation of the endolysosomal system. Abbreviation: AD: Alzheimer disease; LAMP: lysosomal associated membrane protein; LTR: LysoTracker; PD: Parkinson disease; TMEM175: transmembrane protein 175; V-ATPase: vacuolar-type H + -translocating ATPase.