Western blot was performed using anti-CK1 Polyclonal Antibody (Product # PA5-17536) and a 37 kDa band corresponding to CK1 was observed across cell lines tested. Whole cell extracts (30 µg lysate) of HEK 293 (Lane 1), HeLa (Lane 2), HCT 116 (Lane 3), MCF-7 (Lane 4) and A549 (Lane 5) were electrophoresed using NuPAGE™ 4-12% Bis-Tris Protein Gel (Product # NP0322BOX). Resolved proteins were then transferred onto a nitrocellulose membrane (Product # IB23001) by iBlot® 2 Dry Blotting System (Product # IB21001). The blot was probed with the primary antibody (1:1000 dilution) and detected by chemiluminescence with Goat anti-Rabbit IgG (Heavy Chain) Superclonal™ Recombinant Secondary Antibody, HRP (Product # A27036, 1:4000 dilution) using the iBright FL 1000 (Product # A32752). Chemiluminescent detection was performed using Novex® ECL Chemiluminescent Substrate Reagent Kit (Product # WP20005).