RT Journal Article SR Electronic T1 Osteoblastic lysosome plays a central role in mineralization JF Science Advances JO Sci Adv FD American Association for the Advancement of Science SP eaax0672 DO 10.1126/sciadv.aax0672 VO 5 IS 7 A1 Iwayama, Tomoaki A1 Okada, Tomoko A1 Ueda, Tsugumi A1 Tomita, Kiwako A1 Matsumoto, Shuji A1 Takedachi, Masahide A1 Wakisaka, Satoshi A1 Noda, Takeshi A1 Ogura, Taku A1 Okano, Tomomichi A1 Fratzl, Peter A1 Ogura, Toshihiko A1 Murakami, Shinya YR 2019 UL http://advances.sciencemag.org/content/5/7/eaax0672.abstract AB Mineralization is the most fundamental process in vertebrates. It is predominantly mediated by osteoblasts, which secrete mineral precursors, most likely through matrix vesicles (MVs). These vesicular structures are calcium and phosphate rich and contain organic material such as acidic proteins. However, it remains largely unknown how intracellular MVs are transported and secreted. Here, we use scanning electron-assisted dielectric microscopy and super-resolution microscopy for assessing live osteoblasts in mineralizing conditions at a nanolevel resolution. We found that the calcium-containing vesicles were multivesicular bodies containing MVs. They were transported via lysosome and secreted by exocytosis. Thus, we present proof that the lysosome transports amorphous calcium phosphate within mineralizing osteoblasts.