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Original Article |
Correspondence to: Kristen J. Verhey, Department of Cell Biology, Harvard Medical School, 240 Longwood Ave., Boston, MA 02115. Tel:(617) 432-1612 Fax:(617) 432-1190 E-mail:kverhey{at}hms.harvard.edu.
The cargo that the molecular motor kinesin moves along microtubules has been elusive. We searched for binding partners of the COOH terminus of kinesin light chain, which contains tetratricopeptide repeat (TPR) motifs. Three proteins were found, the c-jun NH2-terminal kinase (JNK)interacting proteins (JIPs) JIP-1, JIP-2, and JIP-3, which are scaffolding proteins for the JNK signaling pathway. Concentration of JIPs in nerve terminals requires kinesin, as evident from the analysis of JIP COOH-terminal mutants and dominant negative kinesin constructs. Coprecipitation experiments suggest that kinesin carries the JIP scaffolds preloaded with cytoplasmic (dual leucine zipperbearing kinase) and transmembrane signaling molecules (the Reelin receptor, ApoER2). These results demonstrate a direct interaction between conventional kinesin and a cargo, indicate that motor proteins are linked to their membranous cargo via scaffolding proteins, and support a role for motor proteins in spatial regulation of signal transduction pathways.
Key Words: kinesin, molecular motors, scaffolding protein, JNK signaling, Reelin
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