The position of lysosomes within the cell determines their luminal pH

We examined the luminal pH of individual lysosomes using quantitative ratiometric fluorescence microscopy and report an unappreciated heterogeneity: peripheral lysosomes are less acidic than juxtanuclear ones despite their comparable buffering capacity. An increased passive (leak) permeability to protons, together with reduced vacuolar H(+)-adenosine triphosphatase (V-ATPase) activity, accounts for the reduced acidifying ability of peripheral lysosomes. The altered composition of peripheral lysosomes is due, at least in part, to more limited access to material exported by the biosynthetic pathway. The balance between Rab7 and Arl8b determines the subcellular localization of lysosomes; more peripheral lysosomes…

• HF
  Hospital for Sick Children
• NI
  National Institutes of Health
• CI
  Canadian Institutes of Health Research

  Award: FDN-143202