PTPRB and diabetes mellitus: Tyr81 was found to be phosphorylated by Src [59] and Abl [60] and dephosphorylated by vascular endothelial protein tyrosine phosphatase (VE‐PTP), which is of relevance in as much as VE‐PTP expression is increased by hypoxia [61] and in metabolic conditions such as diabetes [62].