 One way this activation may occur is through disruption of the conformation of sensitive protein phosphatase enzymes; specific phosphatases normally inhibit the activity of JNK itself and the activity of proteins linked to JNK activation.JNKs can associate with scaffold proteins JNK interacting proteins (JIP) as well as their upstream kinases JNKK1 and JNKK2 following their activation.JNK, by phosphorylation, modifies the activity of numerous proteins that reside at the mitochondria or act in the nucleus.