Catalyzes the reversible oxidation of (R)-2-hydroxyglutarate to 2-oxoglutarate coupled to reduction of pyruvate to (R)-lactate. Can also use oxaloacetate as electron acceptor instead of pyruvate producing (R)-malate (PubMed:26774271). In addition to its enzymatic role it could play an important role in the yeast cell morphology (PubMed:10509019). (R)-lactate + 2 Fe(III)-[cytochrome c] = 2 Fe(II)-[cytochrome c] + 2 H(+) + pyruvate (R)-2-hydroxyglutarate + pyruvate = (R)-lactate + 2-oxoglutarate kcat is 0.11 sec(-1) for (R)-2-hydroxyglutarate oxidation with pyruvate as electron acceptor. kcat is 0.18 sec(-1) for (R)-2-hydroxyglutarate oxidation with DCIP as electron acceptor. kcat is 1.31 sec(-1) for (R)-lactate reduction with DCIP as electron donor. Interacts with F-actin. Present with 11400 molecules/cell in log phase SD medium. Belongs to the FAD-binding oxidoreductase/transferase type 4 family.