A molecular ruler determines the repeat length in eukaryotic cilia and flagella.
Existence of cellular structures with specific size raises a fundamental question in biology: How do cells measure length? One conceptual answer to this question is by a molecular ruler, but examples of such rulers in eukaryotes are lacking. In this work, we identified a molecular ruler in eukaryotic cilia and flagella. Using cryo-electron tomography, we found that FAP59 and FAP172 form a 96-nanometer (nm)-long complex in Chlamydomonas flagella and that the absence of the complex disrupted 96-nm repeats of axonemes. Furthermore, lengthening of the FAP59/172 complex by domain duplication resulted in extension of the repeats up to 128 nm, as well as duplication of specific axonemal components. Thus, the FAP59/172 complex is the molecular ruler that determines the 96-nm repeat length and arrangements of components in cilia and flagella.
Department of Cell Biology and Anatomy, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo Bunkyo-ku, Tokyo, 113-0033, Japan.
Toshiyuki
T
Oda
Department of Cell Biology and Anatomy, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo Bunkyo-ku, Tokyo, 113-0033, Japan.
Haruaki
H
Yanagisawa
Department of Biological Science, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo Bunkyo-ku, Tokyo, 113-0033, Japan. Department of Life Science, Faculty of Science, Gakushuin University, 1-5-1 Mejiro, Toshima-ku, Tokyo, 171-8588, Japan.
Ritsu
R
Kamiya
Department of Cell Biology and Anatomy, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo Bunkyo-ku, Tokyo, 113-0033, Japan. mkikkawa@m.u-tokyo.ac.jp.
Masahide
M
Kikkawa
D056444:Axonemal Dyneins / Q000737:chemistry* / Q000235:genetics / Q000648:ultrastructure; D002696:Chlamydomonas / Q000502:physiology* / Q000648:ultrastructure; D002923:Cilia / Q000502:physiology / Q000648:ultrastructure; D005057:Eukaryotic Cells / Q000502:physiology / Q000648:ultrastructure; D005407:Flagella / Q000502:physiology* / Q000648:ultrastructure; D011487:Protein Conformation
D056444:Axonemal Dyneins