MAPK8 and crescentic glomerulonephritis: Indeed, the answer to this question is not obvious as ASK1 is not required for acute IL‐1 or LPS‐induced p38 activation in cultured tubular epithelial cells,23 and IL‐1 contributes to the development of crescentic disease,25 while LPS exacerbates glomerular injury.26 This study used the highly selective ASK1 inhibitor, GS‐444217, to ask whether: (i) an ASK1 inhibitor can suppress p38 and JNK activation in crescentic glomerulonephritis, and (ii) an ASK1 inhibitor can suppress disease development.