“JIP”ing along the axon: the complex roles of JIPs in axonal transport

JIPs are JNK interacting proteins and bind to JNK cascade kinases. JIP1 and JIP3 were known to be adaptors linking cargo to Kinesin-I, a major molecular motor for axonal transport. Recent research sheds further light on JIPs' complex roles in axonal transport, namely in activation of Kinesin-I and in cargo release. In Drosophila, APLIP1/JIP1 allows the Kinesin-I complex to enable cargo release through activation of JNK signaling.1 In mammalian cell culture, JIP1 is necessary and, together with UNC-76/FEZ1, sufficient for activating Kinesin-I.2 I discuss and compare the many roles played by JIP1 and JIP3 through interactions with several distinct players, in retrograde as well as anterograde transport.