Involved in leaf development regulation. H2O + O-phospho-L-seryl-[protein] = L-seryl-[protein] + phosphate H2O + O-phospho-L-threonyl-[protein] = L-threonyl-[protein] + phosphate Binds 2 magnesium or manganese ions per subunit. Expressed in seedlings, roots, leaves, stems, young inflorescences, flowers and siliques. The conserved PP2C phosphatase domain (244-643) is interrupted by an insertion of approximately 100 amino acids. Plants show abnormal leaves altered in shape and curling. Belongs to the PP2C family.