Bifunctional serine/threonine kinase and phosphorylase involved in the dark/light-mediated regulation of PPDK by catalyzing its phosphorylation/dephosphorylation. Has a much lower phosphotransferase activity than PDRP1 (PubMed:21883547). Can use ADP as a high specificity substrate and GDP as a lower affinity substrate, but has no activity with UDP (PubMed:21414960). ADP + N(tele)-phospho-L-histidyl/L-threonyl-[pyruvate, phosphate dikinase] = AMP + H(+) + N(tele)-phospho-L-histidyl/O-phospho-L-threonyl-[pyruvate, phosphate dikinase] H(+) + N(tele)-phospho-L-histidyl/O-phospho-L-threonyl-[pyruvate, phosphate dikinase] + phosphate = diphosphate + N(tele)-phospho-L-histidyl/L-threonyl-[pyruvate, phosphate dikinase] Regulated by light/dark exposure. Interacts with PPDK1. Expressed in pollen and seeds. Was thought to be devoided of phosphorylase activity (PubMed:17996018), but possess a much slower rate of phosphotransferase than PDRP1. Belongs to the pyruvate, phosphate/water dikinase regulatory protein family. PDRP subfamily.