The conversion of nutrient-signaling active anabolic to degradative catabolic lysosomes in starved cells in addition to PI4K2A also involves hydrolysis of lysosomal PI(3)P by the PI 3-phosphatase MTMR14 (64), another enzyme mutated in an autosomal form of myotubular myopathy (129), suggesting that altered lysosome function may contribute to inherited forms of myotubular myopathy. Here, MTMR14 is linked to centronuclear myopathy.