title: Co-operative versus independent transport of different cargoes by Kinesin-1.
abstract: Kinesin motors drive the intracellular transport of multiple cargoes along microtubule tracks; yet, how kinesins discriminate among their many potential cargoes is unknown. We tested whether Kinesin-1 cargoes compete, co-operate or are transported independently of each other. We focused on Kinesin-1 cargoes that bind directly to the kinesin light chain (KLC) subunit, namely the c-Jun NH(2)-terminal kinase-interacting proteins (JIPs) 1 and 3, Kidins220/ARMS and PAT1. Overexpression of individual cargo proteins in differentiated CAD cells resulted in mislocalization of the endogenous protein but had no effect on localization of other cargo proteins to neurite tips. Thus, while transport of distinct cargoes is saturable, they do not compete with each other. Interestingly, we found that low expression of JIP1 or JIP3 enhanced the transport of the other JIP to neurite tips. Moreover, JIP1 and JIP3 require each other for transport. Co-operative transport is due to an interaction between JIP1 and JIP3 as well as distinct binding sites on the KLC tetratricopeptide repeat (TPR) bundle: the TPR groove binds to C-terminal residues of JIP1, whereas the TPR surface binds to internal residues in JIP3. Formation of a JIP1/JIP3/KLC complex is necessary for efficient JIP1 or JIP3 transport in neuronal cells. Thus, JIP scaffolding proteins are transported in a co-operative manner, despite the independent transport of other Kinesin-1 cargoes.
authors.affiliation: Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA.
authors.forename: Jennetta W
authors.initials: JW
authors.lastname: Hammond
authors.forename: Kelly
authors.initials: K
authors.lastname: Griffin
authors.forename: Gloria T
authors.initials: GT
authors.lastname: Jih
authors.forename: Jeanne
authors.initials: J
authors.lastname: Stuckey
authors.forename: Kristen J
authors.initials: KJ
authors.lastname: Verhey
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D000818:Animals; D001665:Binding Sites; D001692:Biological Transport / Q000502:physiology*; D002460:Cell Line; D006801:Humans; D016547:Kinesins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D008958:Models, Molecular; D046912:Multiprotein Complexes / Q000378:metabolism; D009419:Nerve Tissue Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D016501:Neurites / Q000378:metabolism / Q000648:ultrastructure; D011485:Protein Binding; D011487:Protein Conformation; D020033:Protein Isoforms / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D021122:Protein Subunits / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D051381:Rats; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D020798:Two-Hybrid System Techniques
chemical_list: D048868:Adaptor Proteins, Signal Transducing; C490665:Mapk8ip protein, mouse; C486564:Mapk8ip2 protein, mouse; C403619:Mapk8ip3 protein, mouse; D046912:Multiprotein Complexes; D009419:Nerve Tissue Proteins; D020033:Protein Isoforms; D021122:Protein Subunits; D011993:Recombinant Fusion Proteins; D016547:Kinesins