The activation of pH-sensing receptor GPR68 can induce ER stress through the phospho-inositol required 1α/c-Jun N-terminal kinase (IRE1α/JNK) pathway in the intestinal epithelial cells, indicating that the pH-sensing receptor GPR68 downstream IRE1α/JNK pathway are potential treatment targets to improve inflammatory bowel disease [227]. Here, MAPK8 is linked to inflammatory bowel disease.