UNC-83 coordinates kinesin-1 and dynein activities at the nuclear envelope during nuclear migration

Dev Biol. 2010 Feb 15;338(2):237-50. doi: 10.1016/j.ydbio.2009.12.004. Epub 2009 Dec 21.


Nuclei migrate during many events, including fertilization, establishment of polarity, differentiation, and cell division. The Caenorhabditis elegans KASH protein UNC-83 localizes to the outer nuclear membrane where it recruits kinesin-1 to provide the major motor activity required for nuclear migration in embryonic hyp7 cells. Here we show that UNC-83 also recruits two dynein-regulating complexes to the cytoplasmic face of the nucleus that play a regulatory role. One consists of the NudE homolog NUD-2 and the NudF/Lis1/Pac1 homolog LIS-1, and the other includes dynein light chain DLC-1, the BicaudalD homolog BICD-1, and the Egalitarian homologue EGAL-1. Genetic disruption of any member of these two complexes caused nuclear migration defects that were enhanced in some double mutant animals, suggesting that BICD-1 and EGAL-1 function in parallel to NUD-2. Dynein heavy chain mutant animals also had a nuclear migration defect, suggesting these complexes function through dynein. Deletion analysis indicated that independent domains of UNC-83 interact with kinesin and dynein. These data suggest a model where UNC-83 acts as the cargo-specific adaptor between the outer nuclear membrane and the microtubule motors kinesin-1 and dynein. Kinesin-1 functions as the major force generator during nuclear migration, while dynein is involved in regulation of bidirectional transport of the nucleus.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • Biological Transport
  • Caenorhabditis elegans
  • Caenorhabditis elegans Proteins / physiology*
  • Cell Nucleus / physiology*
  • Dyneins / metabolism*
  • Kinesin / metabolism*
  • Membrane Proteins
  • Microtubule-Associated Proteins
  • Multiprotein Complexes
  • Nuclear Envelope / chemistry
  • Nuclear Envelope / metabolism*
  • Nuclear Proteins


  • Caenorhabditis elegans Proteins
  • Membrane Proteins
  • Microtubule-Associated Proteins
  • Multiprotein Complexes
  • Nuclear Proteins
  • Unc-83 protein, C elegans
  • lis-1 protein, C elegans
  • Dyneins
  • Kinesin