increased PC-1 localization in matrix vesicles (MVs) can lead to an accumulation of PPi.

Matsuzawa and colleagues have demonstrated that most MV alkaline phosphatase (ALP) is active on the outer membrane leaflet of MVs, and this ALP can generate Pi which is partially released. However, some ALP may be active at a location other than the external membrane, and it is unclear how this Pi is transported into the MV interior.

It is possible that there are specialized binding or #transport #mechanisms in MV membranes for PPi generated locally by NTPPPH activity.

Further research is needed to investigate this mechanism.