Fig. 2
From: The PHR proteins: intracellular signaling hubs in neuronal development and axon degeneration
A negative regulatory network inhibits the DLK-1 pathway in C. elegans. Shown are the negative regulatory mechanisms that function as a network to restrain the activity of the DLK-1 MAP kinase pathway in the motor neurons and mechanosensory neurons of C. elegans. RPM-1 binds to PPM-2, and PPM-2 directly dephosphorylates and inhibits DLK-1Â L. DLK-1S heterodimerizes with and inhibits DLK-1Â L. RPM-1 and FSN-1 function as a complex to ubiquitinate DLK-1Â L and target it for degradation. Finally, PPM-1 inhibits the DLK-1 pathway, most likely by dephosphorylating and inhibiting PMK-3 or MKK-4