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JNK-interacting protein 3 mediates the retrograde transport of activated c-Jun N-terminal kinase and lysosomes.

Drerup CM, Nechiporuk AV - PLoS Genet. (2013)

Bottom Line: 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.

View Article: PubMed Central - PubMed

Affiliation: Department of Cell and Developmental Biology, Oregon Health & Science University, Portland, Oregon, USA.

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.

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Related in: MedlinePlus

Model of Jip3's role in retrograde transport of lysosomes and pJNK.Our data support a model in which Jip3 (green star) serves as a necessary adapter for retrograde transport of pJNK (yellow hexagon) and lysosomes (red oval). This interaction serves to attach these cargoes to the dynein motor complex and, in the case of lysosomes, likely requires interaction with dynein light intermediate chain (DLIC). Global retrograde transport initiation is unaffected with loss of Jip3 as dynein heavy chain, dynactin and other dynein cargos (late endosomes and autophagosomes) do not accumulate in jip3nl7 mutant axon terminals.
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pgen-1003303-g009: Model of Jip3's role in retrograde transport of lysosomes and pJNK.Our data support a model in which Jip3 (green star) serves as a necessary adapter for retrograde transport of pJNK (yellow hexagon) and lysosomes (red oval). This interaction serves to attach these cargoes to the dynein motor complex and, in the case of lysosomes, likely requires interaction with dynein light intermediate chain (DLIC). Global retrograde transport initiation is unaffected with loss of Jip3 as dynein heavy chain, dynactin and other dynein cargos (late endosomes and autophagosomes) do not accumulate in jip3nl7 mutant axon terminals.

Mentions: Finally, we co-expressed DLIC tagged with mTangerine (mTangerine-DLIC) and Lamp1-EGFP to characterize DLIC localization and co-transport with lysosomes and determine if this association is lost in jip3nl7 mutants. At 3 dpf, mTangerine-DLIC localized to discrete puncta along the axon and in axon terminals in wildtype larvae (Figure 8F). In contrast, in jip3nl7 mutants, DLIC accumulated in axon terminals, similar to lysosomes and pJNK (Figure 8G). Co-transport analysis of mTangerine-DLIC and Lamp1-EGFP cargos revealed a decrease in the ratio of DLIC-positive lysosomes moving in the retrograde direction in jip3nl7 mutants (Figure 8H–8M; Video S11). This observation points to a failure of lysosome-dynein interaction during transport with loss of Jip3. Interestingly, there was a slight decrease in DLIC-Lamp1 vesicle co-transport in the anterograde direction as well in jip3nl7 mutants suggesting that this complex may move bidirectionally. In summary, our data supports a model where the independent interaction of Jip3 with pJNK and lysosomes is required for the attachment of these cargoes to the dynein motor for clearance from axon terminals (Figure 9).


JNK-interacting protein 3 mediates the retrograde transport of activated c-Jun N-terminal kinase and lysosomes.

Drerup CM, Nechiporuk AV - PLoS Genet. (2013)

Model of Jip3's role in retrograde transport of lysosomes and pJNK.Our data support a model in which Jip3 (green star) serves as a necessary adapter for retrograde transport of pJNK (yellow hexagon) and lysosomes (red oval). This interaction serves to attach these cargoes to the dynein motor complex and, in the case of lysosomes, likely requires interaction with dynein light intermediate chain (DLIC). Global retrograde transport initiation is unaffected with loss of Jip3 as dynein heavy chain, dynactin and other dynein cargos (late endosomes and autophagosomes) do not accumulate in jip3nl7 mutant axon terminals.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3585007&req=5

pgen-1003303-g009: Model of Jip3's role in retrograde transport of lysosomes and pJNK.Our data support a model in which Jip3 (green star) serves as a necessary adapter for retrograde transport of pJNK (yellow hexagon) and lysosomes (red oval). This interaction serves to attach these cargoes to the dynein motor complex and, in the case of lysosomes, likely requires interaction with dynein light intermediate chain (DLIC). Global retrograde transport initiation is unaffected with loss of Jip3 as dynein heavy chain, dynactin and other dynein cargos (late endosomes and autophagosomes) do not accumulate in jip3nl7 mutant axon terminals.
Mentions: Finally, we co-expressed DLIC tagged with mTangerine (mTangerine-DLIC) and Lamp1-EGFP to characterize DLIC localization and co-transport with lysosomes and determine if this association is lost in jip3nl7 mutants. At 3 dpf, mTangerine-DLIC localized to discrete puncta along the axon and in axon terminals in wildtype larvae (Figure 8F). In contrast, in jip3nl7 mutants, DLIC accumulated in axon terminals, similar to lysosomes and pJNK (Figure 8G). Co-transport analysis of mTangerine-DLIC and Lamp1-EGFP cargos revealed a decrease in the ratio of DLIC-positive lysosomes moving in the retrograde direction in jip3nl7 mutants (Figure 8H–8M; Video S11). This observation points to a failure of lysosome-dynein interaction during transport with loss of Jip3. Interestingly, there was a slight decrease in DLIC-Lamp1 vesicle co-transport in the anterograde direction as well in jip3nl7 mutants suggesting that this complex may move bidirectionally. In summary, our data supports a model where the independent interaction of Jip3 with pJNK and lysosomes is required for the attachment of these cargoes to the dynein motor for clearance from axon terminals (Figure 9).

Bottom Line: 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.

View Article: PubMed Central - PubMed

Affiliation: Department of Cell and Developmental Biology, Oregon Health & Science University, Portland, Oregon, USA.

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.

Show MeSH
Related in: MedlinePlus