The C. elegans RSA complex localizes protein phosphatase 2A to centrosomes and regulates mitotic spindle assembly

Cell. 2007 Jan 12;128(1):115-27. doi: 10.1016/j.cell.2006.10.050.

Abstract

Microtubule behavior changes during the cell cycle and during spindle assembly. However, it remains unclear how these changes are regulated and coordinated. We describe a complex that targets the Protein Phosphatase 2A holoenzyme (PP2A) to centrosomes in C. elegans embryos. This complex includes Regulator of Spindle Assembly 1 (RSA-1), a targeting subunit for PP2A, and RSA-2, a protein that binds and recruits RSA-1 to centrosomes. In contrast to the multiple functions of the PP2A catalytic subunit, RSA-1 and RSA-2 are specifically required for microtubule outgrowth from centrosomes and for spindle assembly. The centrosomally localized RSA-PP2A complex mediates these functions in part by regulating two critical mitotic effectors: the microtubule destabilizer KLP-7 and the C. elegans regulator of spindle assembly TPXL-1. By regulating a subset of PP2A functions at the centrosome, the RSA complex could therefore provide a means of coordinating microtubule outgrowth from centrosomes and kinetochore microtubule stability during mitotic spindle assembly.

MeSH terms

  • Animals
  • Caenorhabditis elegans / cytology
  • Caenorhabditis elegans / embryology
  • Caenorhabditis elegans / metabolism*
  • Caenorhabditis elegans Proteins / metabolism
  • Carrier Proteins / metabolism
  • Catalysis
  • Centrosome / metabolism*
  • Dimerization
  • Embryo, Nonmammalian / abnormalities
  • Embryo, Nonmammalian / cytology
  • Embryo, Nonmammalian / ultrastructure
  • Kinesin / metabolism
  • Microtubules / metabolism
  • Multiprotein Complexes / metabolism*
  • Phosphoprotein Phosphatases / metabolism*
  • Protein Binding
  • Protein Phosphatase 2
  • Protein Subunits / metabolism
  • Protein Transport
  • Spindle Apparatus / metabolism*

Substances

  • Caenorhabditis elegans Proteins
  • Carrier Proteins
  • Multiprotein Complexes
  • Protein Subunits
  • TPXL-1 protein, C elegans
  • Phosphoprotein Phosphatases
  • Protein Phosphatase 2
  • Kinesin