A regulatory light chain of ciliary outer arm dynein in Tetrahymena thermophila
Research output: Contribution to journal › Journal article › Research › peer-review
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 approximately 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 language | English |
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Journal | Journal of Biological Chemistry |
Volume | 276 |
Issue number | 23 |
Pages (from-to) | 20048-54 |
Number of pages | 6 |
ISSN | 0021-9258 |
DOIs | |
Publication status | Published - 2001 |
Externally published | Yes |
Bibliographical note
Keywords: Animals; Calcium; Cilia; Cyclic AMP; Dynein ATPase; Electrophoresis, Polyacrylamide Gel; Phosphorylation; Tetrahymena thermophila
ID: 11255436