Figure 3.

Deletion of both Vxc1p and Pmc1p results in low sensitivity to Ca²⁺ but does not impair fusion activity. (A) Vacuoles were isolated from our normal tester strains and pmc1Δ vcx1Δ derivatives, then incubated for 90 min at 27°C in the presence of ATP and CaCl₂, and phosphatase was assayed. (B) Fusion of wild-type and pmc1Δ vcx1Δ vacuoles. Vacuoles were incubated in reaction buffer and ATP for 90 min at 27°C in the presence of CaM (7.5 μM), CA (250 μM), BAPTA (5 mM), and CaCl₂, and alkaline phosphatase activity was measured.