Western blots were performed as described [6 (link),9 (link),34 (link)].
The primary antibodies for WB, PTP, and Imaging were: Rabbit anti-pVAV1 (Y160) (Bio Source Cat# Bs44482, Invitrogen, Thermofisher); human anti-CD28 (BioLegend, London, United Kingdom Cat# 302934); Rabbit anti-SHP-1 (C-19) (Santa-Cruz Biotechnology, Heidelberg, Germany, Cat# sc-287); Mouse anti-GAPDH (0411) (Santa-Cruz Biotechnology, Heidelberg, Germany, Cat# sc-47724); and Mouse anti-WASp (D1) (Santa-Cruz Biotechnology, Heidelberg, Germany, Cat# sc-5300).
Secondary Antibodies were: Goat anti-Rabbit (Santa Cruz Biotechnology, Heidelberg, Germany, Cat# sc-2004) and Goat anti-Mouse (Jackson ImmunoResearch, West Grove, PA, USA, cat# 115-035-003).