PTPN11 and osteoporosis: Several PTPs are attractive pharmacological targets, including cyt-PTPε for osteoporosis,26,137 SHP2 for cartilage regeneration,36 and RPTPζ for IVD anti-degeneration.213 Despite promising progress in developing chemically allosteric inhibitors,268–270 finding specific, cell-permeable, and clinically effective compounds for PTPs, in contrast to PTKs, remains challenging due to the cellular context-specific effects and the lack of cell permeability and selectivity across members of the PTP family.