Jump-starting kinesin.
When it is not actively transporting cargo, conventional Kinesin-1 is present in the cytoplasm in a folded conformation that cannot interact effectively with microtubules (MTs). Two important and largely unexplored aspects of kinesin regulation are how it is converted to an active species when bound to cargo and the related issue of how kinesin discriminates among its many potential cargo molecules. Blasius et al. (see p. 11 of this issue) report that either binding of the cargo linker c-Jun N-terminal kinase-interacting protein 1 (JIP1) to the light chains (LCs) or binding of fasciculation and elongation protein zeta1 (FEZ1) to the heavy chains (HCs) is insufficient for activation but that activation occurs when both are present simultaneously. A related paper by Cai et al. (see p. 51 of this issue) provides structural insight into the conformation of the folded state in the cell obtained by fluorescence resonance energy transfer analysis.
Hackney
David D
DD
Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213, USA. ddh@andrew.cmu.edu
D048868:Adaptor Proteins, Signal Transducing / Q000378:metabolism; D000818:Animals; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000378:metabolism; D004330:Drosophila; D006801:Humans; D016547:Kinesins / Q000737:chemistry / Q000378:metabolism*; D008869:Microtubule-Associated Proteins / Q000378:metabolism; D009419:Nerve Tissue Proteins; D011485:Protein Binding; D021381:Protein Transport; D051381:Rats; D025521:Tumor Suppressor Proteins / Q000737:chemistry / Q000378:metabolism
D048868:Adaptor Proteins, Signal Transducing; D004268:DNA-Binding Proteins; C528597:FEZ1 protein, human; C118711:LZTS1 protein, human; C490666:MAPK8IP1 protein, human; D008869:Microtubule-Associated Proteins; D009419:Nerve Tissue Proteins; D025521:Tumor Suppressor Proteins; D016547:Kinesins