Preprint Highlight: Sugar transporter Slc37a2 regulates bone metabolism via a dynamic tubular lysosomal network in osteoclasts.

Despite the importance of osteoclast secretory lysosomes (SLs) in bone digestion and resorption, the proteins that reside on SLs are undercharacterized. The authors show that SLC37a2, a unique member of the SLC37 family of sugar ER transporters, localizes to osteoclast SLs and SL tubular networks that support bone resorption. SLC37a2-deficient osteoclasts showed impaired SL membrane tubulation and increased SL size and accumulated monosaccharides, reminiscent of lysosomal storage disorders. Mice lacking SLC37a2 had increased bone mass and strength. As SLC transporters quickly become recognized as metabolic hot spots, SLC37a2 is emerging as a new regulator of lysosomal membrane dynamics and a promising therapeutic target for metabolic bone diseases.