A regulatory light chain of ciliary outer arm dynein in Tetrahymena thermophila

Citation
St. Christensen et al., A regulatory light chain of ciliary outer arm dynein in Tetrahymena thermophila, J BIOL CHEM, 276(23), 2001, pp. 20048-20054
Citations number
28
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Biochemistry & Biophysics
Journal title
JOURNAL OF BIOLOGICAL CHEMISTRY
ISSN journal
0021-9258 → ACNP
Volume
276
Issue
23
Year of publication
2001
Pages
20048 - 20054
Database
ISI
SICI code
0021-9258(20010608)276:23<20048:ARLCOC>2.0.ZU;2-M
Abstract
Ciliary beat frequency is primarily regulated by outer arm dyneins (22 S dy nein), Chilcote and Johnson (Chilcote, T. J., and Johnson, K. A. (1990) J. Biol Chem, 256, 17257-17266) previously studied isolated Tetrahymena 22 S d ynein, identifying a protein p34, which showed cAMP-dependent phosphorylati on, Here, we characterize the molecular biochemistry of p34 further, demons trating that it is the functional ortholog of the 22 S dynein regulatory li ght chain, p29, in Paramecium, p34, thiophosphorylated in isolated axonemes in the presence of cAMP, co-purified with 22 S dynein and not with inner a rm dynein (14 S dynein), Isolated 22 S dynein containing phosphorylated p34 showed similar to 70% increase in in vitro microtubule translocation veloc ity compared with its unphosphorylated counterpart. Extracted p34 rebound t o 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 wa s competitive with p29, Phosphorylated p34 was not present in axonemes isol ated from a mutant lacking outer arms. Two-dimensional gel electrophoresis followed by phosphorimaging revealed at least five phosphorylated p34-relat ed 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 velocit y and consequently ciliary beat frequency through phosphorylation.