Sodium-coupled metabolite transporter that plays a crucial role in pyruvate transport across the chloroplast envelope. Is required for sodium-coupled pyruvate import into plastids. Expressed in developing leaves. No visible phenotype under normal growth conditions, but plants show increased sensitivity to mevastatin, an inhibitor of cytosolic isopentenyl diphosphate biosynthesis. Chloroplasts isolated from mutant plants lack sodium-dependent pyruvate uptake activity. Belongs to the bile acid:sodium symporter (BASS) (TC 2.A.28) family. Truncated N-terminus.