INS and type 2 diabetes mellitus: Here, using immunofluorescence staining with FKBP5 and insulin in human pancreatic tissues from non-diabetic or T2D individuals, we found that FKBP5 has a substantial expression in β cells in non-diabetics, but the expression intensity significantly decreased in T2D; in non-diabetics, there were few β cells without FKBP5 expression, but this phenomenon is more common in T2D islets (Fig. 6A).