Acts as a catabolic phospho-lyase on both gamma- and beta-phosphorylated substrates. Degrades O-phospho-threonine (PThr) to alpha-ketobutyrate, ammonia and phosphate (By similarity). Potent inducer of osteoblastic production of IL6. May act to exacerbate inflammation and/or bone turnover under inflammatory conditions. Secreted by activated T-cells via a calcineurin-independent pathway. Belongs to the threonine synthase family. Truncated N-terminus.