c-Jun N-terminal kinases (JNKs) phosphorylate and augment transcriptional activity of c-Jun. JNKs originate from three genes that yield 10 isoforms through alternative mRNA splicing, including JNK1a1,JNK1b1, JNK2a1, JNK2b1, and JNK3a1, which represent the p46 isoforms,