A Regulatory Light Chain of Ciliary Outer Arm Dynein in Tetrahymena thermophila

Søren Tvorup Christensen, Charles Guerra, Yuuko Wada, Tyson Valentin, Ruth Hogue Angeletti, Peter Satir, Toshikazu Hamasaki

Research output: Contribution to journalArticlepeer-review

40 Scopus citations


Ciliary beat frequency is primarily regulated by outer arm dyneins (22 S dynein). Chilcote and Johnson (Chilcote, T. J., and Johnson, K. A. (1990) J. Biol. Chem. 256, 17257-17266) previously studied isolated Tetrahymena 22 S dynein, identifying a protein p34, which showed cAMP-dependent phosphorylation. Here, we characterize the molecular biochemistry of p34 further, demonstrating that it is the functional ortholog of the 22 S dynein regulatory light chain, p29, in Paramecium. p34, thiophosphorylated in isolated axonemes in the presence of cAMP, co-purified with 22 S dynein and not with inner arm dynein (14 S dynein). Isolated 22 S dynein containing phosphorylated p34 showed ∼70% increase in in vitro microtubule translocation velocity compared with its unphosphorylated counterpart. Extracted p34 rebound to isolated 22 S dynein from either Tetrahymena or Paramecium but not to 14 S dynein from either ciliate. Binding of radiolabeled p34 to 22 S dynein was competitive with p29. Phosphorylated p34 was not present in axonemes isolated from a mutant lacking outer arms. Two-dimensional gel electrophoresis followed by phosphorimaging revealed at least five phosphorylated p34-related spots, consistent with multiple phosphorylation sites in p34 or perhaps multiple isoforms of p34. These new features suggest that a class of outer arm dynein light chains including p34 regulates microtubule sliding velocity and consequently ciliary beat frequency through phosphorylation.

Original languageEnglish (US)
Pages (from-to)20048-20054
Number of pages7
JournalJournal of Biological Chemistry
Issue number23
StatePublished - Jun 8 2001
Externally publishedYes

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology


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