Similarly, ALP was expressed as functional enzyme (Figure , g, Figure ) and induced calcium phosphate precipitation (Figure ). In contrast to the studies above, the enzyme formed calcium phosphate cores inside of the GUVs that in some cases extended and deformed the vesicle membrane so that protrusions formed (Figure , Figure ). We speculate that the difference in morphology between GUV-calcium phosphate structures obtained by ALP expressed in situ compared to directly encapsulated ALP might be a consequence of a lower concentration of enzyme inside of the GUVs in the former case, causing a lower production of calcium phosphate that then precipitated within the lumen of the vesicles without destabilizing their membranes.