TCPTP activation and competition assays with α1-cyt with agonists identified in the screen. A. Small molecules were tested at the indicated concentrations using recombinant TC45 in a DiFMUP phosphatase assay (mean ± SD; n = 3) (due to limited availability N21 was tested only with 10 μM). B. Small molecule activators (10 μM) and α1-cyt peptide (10 μM) were compared for their ability to activate TC45 (mean ± SD; n = 3; ***, p < 0.001). C-D. Direct binding of recombinant purified TC45 to biotinylated integrin α1 cytoplasmic tail was analysed using ELISA assay in the presence or absence of the indicated compounds. C. 11 μM integrin α1 and α2-cytoplasmic domains and D. 1 and 10 μM small molecule compounds were tested for their ability to compete with α1-tail for binding to TC45 (mean ± SD; three parallel measurements from 2 independent experiments **, p < 0.005 ***, p < 0.001).