(A) Matrix calcium content was quantified from PiT-1 ΔSM VSMCs expressing vector control, PiT-1 WT, or PiT-1-E74K that were induced to mineralize in normal Pi (1.0 mM) or elevated Pi (2.6 mM) for 8 days. (B) Rate of apoptosis was determined after incubation in normal or elevated Pi for 2 or 5 days. (C) Calcification was quantified of PiT-1 ΔSM VSMCs expressing vector control, PiT-1 WT, PiT-1-E74K, PiT-1-S132A, or PiT-1-S623A, and data is presented as fold-induction over vector control for each experiment by cell line. (D) Correlation analysis between calcification and calculated sodium-dependent Pi uptake Vmax parameter for each cell line is presented, with a horizontal dash indicating average value of data points and a dashed regression line with the coefficient of correlation indicating linear correlation. Data is presented as mean ± S.D. (A–C), or as single points for linear regression (D). Statistically significant differences between indicated means (A) or compared to vector control (C) are indicated by * = P<0.05, determined by One-way ANOVA post-hoc Tukey analysis.