Adam9

Lysates from cells and tissues were prepared using RIPA buffer containing a protease inhibitor cocktail (Sigma‐Aldrich, Merck, kGaA, Darmstadt, Germany). Proteins were separated using SDS/PAGE gels and were electrotransferred to nitrocellulose filter membranes (Millipore, Bedford, MA, USA). The membranes were blocked in 5% non‐fat milk and immunoblotted with primary specific antibodies overnight at 4 °C, followed by their respective secondary antibodies. The primary antibodies were used as follows: ADAM9 (#ab186833; Abcam, Cambridge, MA, USA), USP39 (#ab131244; Abcam), integrin β1 (#34971; CST, Danvers, MA, USA), GAPDH (#60004‐1‐Ig; Proteintech, Wuhan, China), β‐Actin (#AA128; Hua An Biotechnology, Hangzhou, China).

Immunohistochemistry was performed as described previously47 (link). In brief, paraffin-embedded tissue sections (5 μm) were deparaffinized, hydrated and washed in TBS (10 mM/l Tris HCl, 0.85% NaCl, and pH 7.5) containing 0.1% bovine serum albumin. Endogenous peroxidase activity was quenched by incubating the slides in methanol and 0.6% H₂O₂ in methanol. In all cases, the primary antibody, namely MERTK (1:100), phospho-MERTK (1:50) and ADAM9 (1:50) (Abcam, Cambridge, MA), was incubated overnight at 4 °C. The slides were washed in TBS, and HRP-conjugated secondary antibody (Santa Cruz Bio-technology, Dallas, Texas) was added and the sections were further incubated at room temperature for 45 min. The sections were washed in TBS and incubated with diaminobenzidine tetrahydrochloride as the substrate, and counterstained with hematoxylin and observed under light microscope.