title: JNK-interacting protein 3 mediates the retrograde transport of activated c-Jun N-terminal kinase and lysosomes.
abstract: Retrograde axonal transport requires an intricate interaction between the dynein motor and its cargo. What mediates this interaction is largely unknown. Using forward genetics and a novel in vivo imaging approach, we identified JNK-interacting protein 3 (Jip3) as a direct mediator of dynein-based retrograde transport of activated (phosphorylated) c-Jun N-terminal Kinase (JNK) and lysosomes. Zebrafish jip3 mutants (jip3(nl7) ) displayed large axon terminal swellings that contained high levels of activated JNK and lysosomes, but not other retrograde cargos such as late endosomes and autophagosomes. Using in vivo analysis of axonal transport, we demonstrated that the terminal accumulations of activated JNK and lysosomes were due to a decreased frequency of retrograde movement of these cargos in jip3(nl7) , whereas anterograde transport was largely unaffected. Through rescue experiments with Jip3 engineered to lack the JNK binding domain and exogenous expression of constitutively active JNK, we further showed that loss of Jip3-JNK interaction underlies deficits in pJNK retrograde transport, which subsequently caused axon terminal swellings but not lysosome accumulation. Lysosome accumulation, rather, resulted from loss of lysosome association with dynein light intermediate chain (dynein accessory protein) in jip3(nl7) , as demonstrated by our co-transport analyses. Thus, our results demonstrate that Jip3 is necessary for the retrograde transport of two distinct cargos, active JNK and lysosomes. Furthermore, our data provide strong evidence that Jip3 in fact serves as an adapter protein linking these cargos to dynein.
authors.affiliation: Department of Cell and Developmental Biology, Oregon Health & Science University, Portland, Oregon, USA.
authors.forename: Catherine M
authors.initials: CM
authors.lastname: Drerup
authors.forename: Alex V
authors.initials: AV
authors.lastname: Nechiporuk
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D001370:Axonal Transport / Q000235:genetics*; D004398:Dyneins / Q000235:genetics / Q000378:metabolism*; D011992:Endosomes / Q000235:genetics / Q000378:metabolism; D005786:Gene Expression Regulation; D006801:Humans; D048031:JNK Mitogen-Activated Protein Kinases / Q000235:genetics / Q000378:metabolism; D008247:Lysosomes / Q000235:genetics / Q000378:metabolism; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism; D010766:Phosphorylation; D015027:Zebrafish / Q000235:genetics / Q000378:metabolism; D029961:Zebrafish Proteins / Q000378:metabolism*
chemical_list: D048868:Adaptor Proteins, Signal Transducing; C485750:MAPK8IP3 protein, human; D009419:Nerve Tissue Proteins; D029961:Zebrafish Proteins; C581624:mapk8ip3 protein, zebrafish; D048031:JNK Mitogen-Activated Protein Kinases; D004398:Dyneins