To investigate the contribution of myeloid cell-expressed ASK1 to the development of obesity and glucose intolerance, we generated myeloid cell-specific ASK1 knockout mice (ASK1flox/flox, Lysozyme-cre+/−; ASK1Δmye) using the Cre-lox system. Here, MAP3K5 is linked to obesity due to melanocortin 4 receptor deficiency.