Minhee Kim, Jin Hee Park, Miyeon Go, Nawon Lee, Jeongin Seo, Hana Lee, Doyong Kim, Hyunil Ha, Taesoo Kim, Myeong Seon Jeong, Suree Kim, Taesoo Kim, Han Sung Kim, Dongmin Kang, Hyunbo Shim, Soo Young Lee
Mature osteoclasts degrade bone matrix by exocytosis of active proteases from secretory lysosomes through a ruffled border. However, the molecular mechanisms underlying lysosomal trafficking and secretion in osteoclasts remain largely unknown. Here, we show with GeneChip analysis that RUN and FYVE domain-containing protein 4 (RUFY4) is strongly upregulated during osteoclastogenesis. Mice lacking Rufy4 exhibited a high trabecular bone mass phenotype with abnormalities in osteoclast function in vivo. Furthermore, deleting Rufy4 did not affect osteoclast differentiation, but inhibited bone-resorbing activity due to disruption in the acidic maturation of secondary lysosomes, their trafficking to the membrane, and their secretion of cathepsin K into the extracellular space...
May 15, 2024: Bone Research