Western blot was performed using Anti-p38 MAPK gamma Polyclonal Antibody (Product # PA5-17371) and a 41kDa band corresponding to Mitogen-activated protein kinase 12 was observed in Mouse Skeletal muscle and Rat Skeletal Muscle, but not in the other tested tissues. Whole cell extracts (30 µg lysate) of Mouse Thymus (Lane 1), Mouse Liver (Lane 2), Mouse Skeletal Muscle (Lane 3), Rat Liver (Lane 4), Rat Kidney (Lane 5), Rat Brain (Lane 6), Rat Skeletal Muscle (Lane 7) were electrophoresed using NuPAGE™ 10% Bis-Tris Protein Gel (Product # NP0301BOX). 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).