Mutant kinesin-2 motor subunits increase chromosome loss

Mol Biol Cell. 2005 Aug;16(8):3810-20. doi: 10.1091/mbc.e05-05-0404. Epub 2005 Jun 8.


The Chlamydomonas anterograde intraflagellar transport motor, kinesin-2, is isolated as a heterotrimeric complex containing two motor subunits and a nonmotor subunit known as kinesin-associated polypeptide or KAP. One of the two motor subunits is encoded by the FLA10 gene. The sequence of the second motor subunit was obtained by mass spectrometry and sequencing. It shows 46.9% identity with the Fla10 motor subunit and the gene maps to linkage group XII/XIII near RPL9. The temperature-sensitive flagellar assembly mutants fla1 and fla8 are linked to this kinesin-2 motor subunit. In each strain, a unique single point mutation gives rise to a unique single amino acid substitution within the motor domain. The fla8 strain is named fla8-1 and the fla1 strain is named fla8-2. The fla8 and fla10 alleles show a chromosome loss phenotype. To analyze this chromosome loss phenotype, intragenic revertants of fla8-1, fla8-2, and fla10-14 were generated. The analysis of the mutants and the revertants demonstrates the importance of a pocket in the amino terminus of these motor subunits for both motor activity and for a novel, dominant effect on the fidelity of chromosome segregation.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Alleles
  • Amino Acid Sequence
  • Animals
  • Cells, Cultured
  • Chlamydomonas / cytology
  • Chlamydomonas / genetics*
  • Chlamydomonas / metabolism*
  • Chromosomes / genetics
  • Chromosomes / metabolism*
  • Kinesin / chemistry
  • Kinesin / genetics*
  • Kinesin / metabolism*
  • Microtubule-Associated Proteins / chemistry
  • Microtubule-Associated Proteins / genetics
  • Microtubule-Associated Proteins / metabolism
  • Mitosis / radiation effects
  • Molecular Sequence Data
  • Mutation / genetics
  • Protein Subunits / chemistry
  • Protein Subunits / genetics
  • Protein Subunits / metabolism
  • Protozoan Proteins / chemistry*
  • Protozoan Proteins / genetics
  • Protozoan Proteins / metabolism*
  • Sequence Alignment


  • Microtubule-Associated Proteins
  • Protein Subunits
  • Protozoan Proteins
  • Kinesin