Yamazaki and colleagues contributed to the pharmacology of diabetes by noting that the diterpene marine alkaloid agelasine G (124) isolated from the Japanese marine sponge Agelas nakamurai selectively inhibited protein tyrosine phosphase B (PTP1B) and enhanced insulin-stimulated phosphorylation of serine/threonine protein kinase B or Akt in vitro, noting that further studies may “provide a candidate for anti-diabetes therapeutic agents” [151]. This evidence concerns the gene PTPN1 and diabetes mellitus.