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Sunday Driver links axonal transport to damage signaling.

Cavalli V, Kujala P, Klumperman J, Goldstein LS - J. Cell Biol. (2005)

Bottom Line: We found that syd and JNK3 are present on vesicular structures in axons, are transported in both the anterograde and retrograde axonal transport pathways, and interact with kinesin-I and the dynactin complex.Finally, we found that injury induces an enhanced interaction between syd and dynactin.Thus, a mobile axonal JNK-syd complex may generate a transport-dependent axonal damage surveillance system.

View Article: PubMed Central - PubMed

Affiliation: Department of Cellular and Molecular Medicine, Howard Hughes Medical Institute, University of California, San Diego, La Jolla, CA 92093, USA.

ABSTRACT
Neurons transmit long-range biochemical signals between cell bodies and distant axonal sites or termini. To test the hypothesis that signaling molecules are hitchhikers on axonal vesicles, we focused on the c-Jun NH2-terminal kinase (JNK) scaffolding protein Sunday Driver (syd), which has been proposed to link the molecular motor protein kinesin-1 to axonal vesicles. We found that syd and JNK3 are present on vesicular structures in axons, are transported in both the anterograde and retrograde axonal transport pathways, and interact with kinesin-I and the dynactin complex. Nerve injury induces local activation of JNK, primarily within axons, and activated JNK and syd are then transported primarily retrogradely. In axons, syd and activated JNK colocalize with p150Glued, a subunit of the dynactin complex, and with dynein. Finally, we found that injury induces an enhanced interaction between syd and dynactin. Thus, a mobile axonal JNK-syd complex may generate a transport-dependent axonal damage surveillance system.

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Syd and JNK3 form a complex in vivo. (A) Sciatic nerve cross sections were stained for JNK3 and S100. Red arrows, JNK3 puncta; green arrows, Schwann cells. (B) Partial colocalization (arrowheads) is observed between syd and JNK3 puncta in longitudinal sciatic nerve sections within a single axon. (C) Coimmunoprecipitation with syd, P-JNK, JNK3, or no antibodies was performed from brain extract and probed with the indicated antibodies. A fraction of JNK3 is associated with syd (the JNK3 signal for the P-JNK and JNK3 lanes cannot be detected as a result of masking by the IgGs). Bars: (A) 5 μm; (B) 2 μm.
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fig2: Syd and JNK3 form a complex in vivo. (A) Sciatic nerve cross sections were stained for JNK3 and S100. Red arrows, JNK3 puncta; green arrows, Schwann cells. (B) Partial colocalization (arrowheads) is observed between syd and JNK3 puncta in longitudinal sciatic nerve sections within a single axon. (C) Coimmunoprecipitation with syd, P-JNK, JNK3, or no antibodies was performed from brain extract and probed with the indicated antibodies. A fraction of JNK3 is associated with syd (the JNK3 signal for the P-JNK and JNK3 lanes cannot be detected as a result of masking by the IgGs). Bars: (A) 5 μm; (B) 2 μm.

Mentions: Syd and JNK3 have been shown to interact in vitro, when isolated from cotransfected cells (Ito et al., 1999; Kelkar et al., 2000). Similarly to syd, JNK3 showed a punctate pattern in sciatic nerve axons (Fig. 2 A). These results are in agreement with the observation that a significant fraction of JNK3 is biochemically associated with membrane (Fig. 1 A). To further test whether or not syd and JNK3 are found in a complex in vivo, we performed high resolution imaging of single axons stained with syd and JNK3.There is significant overlap between JNK3 and syd positive puncta in axons indicating that they reside, at least in part, in the same axonal compartment. A complete overlap was not expected because JNK3 also binds other scaffolding proteins, including JIP1, JIP2 (Yasuda et al., 1999), and β-arrestin-2 (McDonald et al., 2000). Next, we performed coimmunoprecipitation from mouse brain extracts. A small but significant fraction of JNK3 can be immunoprecipitated with the syd NH2-terminal antibody (Fig. 2 C). The reverse experiment shows that syd can be coimmunoprecipitated with antibodies directed against JNK3 and P-JNK. As a negative control syntaxin is not detected in the coimmunoprecipitations.


Sunday Driver links axonal transport to damage signaling.

Cavalli V, Kujala P, Klumperman J, Goldstein LS - J. Cell Biol. (2005)

Syd and JNK3 form a complex in vivo. (A) Sciatic nerve cross sections were stained for JNK3 and S100. Red arrows, JNK3 puncta; green arrows, Schwann cells. (B) Partial colocalization (arrowheads) is observed between syd and JNK3 puncta in longitudinal sciatic nerve sections within a single axon. (C) Coimmunoprecipitation with syd, P-JNK, JNK3, or no antibodies was performed from brain extract and probed with the indicated antibodies. A fraction of JNK3 is associated with syd (the JNK3 signal for the P-JNK and JNK3 lanes cannot be detected as a result of masking by the IgGs). Bars: (A) 5 μm; (B) 2 μm.
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Related In: Results  -  Collection

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fig2: Syd and JNK3 form a complex in vivo. (A) Sciatic nerve cross sections were stained for JNK3 and S100. Red arrows, JNK3 puncta; green arrows, Schwann cells. (B) Partial colocalization (arrowheads) is observed between syd and JNK3 puncta in longitudinal sciatic nerve sections within a single axon. (C) Coimmunoprecipitation with syd, P-JNK, JNK3, or no antibodies was performed from brain extract and probed with the indicated antibodies. A fraction of JNK3 is associated with syd (the JNK3 signal for the P-JNK and JNK3 lanes cannot be detected as a result of masking by the IgGs). Bars: (A) 5 μm; (B) 2 μm.
Mentions: Syd and JNK3 have been shown to interact in vitro, when isolated from cotransfected cells (Ito et al., 1999; Kelkar et al., 2000). Similarly to syd, JNK3 showed a punctate pattern in sciatic nerve axons (Fig. 2 A). These results are in agreement with the observation that a significant fraction of JNK3 is biochemically associated with membrane (Fig. 1 A). To further test whether or not syd and JNK3 are found in a complex in vivo, we performed high resolution imaging of single axons stained with syd and JNK3.There is significant overlap between JNK3 and syd positive puncta in axons indicating that they reside, at least in part, in the same axonal compartment. A complete overlap was not expected because JNK3 also binds other scaffolding proteins, including JIP1, JIP2 (Yasuda et al., 1999), and β-arrestin-2 (McDonald et al., 2000). Next, we performed coimmunoprecipitation from mouse brain extracts. A small but significant fraction of JNK3 can be immunoprecipitated with the syd NH2-terminal antibody (Fig. 2 C). The reverse experiment shows that syd can be coimmunoprecipitated with antibodies directed against JNK3 and P-JNK. As a negative control syntaxin is not detected in the coimmunoprecipitations.

Bottom Line: We found that syd and JNK3 are present on vesicular structures in axons, are transported in both the anterograde and retrograde axonal transport pathways, and interact with kinesin-I and the dynactin complex.Finally, we found that injury induces an enhanced interaction between syd and dynactin.Thus, a mobile axonal JNK-syd complex may generate a transport-dependent axonal damage surveillance system.

View Article: PubMed Central - PubMed

Affiliation: Department of Cellular and Molecular Medicine, Howard Hughes Medical Institute, University of California, San Diego, La Jolla, CA 92093, USA.

ABSTRACT
Neurons transmit long-range biochemical signals between cell bodies and distant axonal sites or termini. To test the hypothesis that signaling molecules are hitchhikers on axonal vesicles, we focused on the c-Jun NH2-terminal kinase (JNK) scaffolding protein Sunday Driver (syd), which has been proposed to link the molecular motor protein kinesin-1 to axonal vesicles. We found that syd and JNK3 are present on vesicular structures in axons, are transported in both the anterograde and retrograde axonal transport pathways, and interact with kinesin-I and the dynactin complex. Nerve injury induces local activation of JNK, primarily within axons, and activated JNK and syd are then transported primarily retrogradely. In axons, syd and activated JNK colocalize with p150Glued, a subunit of the dynactin complex, and with dynein. Finally, we found that injury induces an enhanced interaction between syd and dynactin. Thus, a mobile axonal JNK-syd complex may generate a transport-dependent axonal damage surveillance system.

Show MeSH
Related in: MedlinePlus