PT  - JOURNAL ARTICLE
AU  - Girish R. Mali
AU  - Ferdos Abid Ali
AU  - Clinton K. Lau
AU  - Farida Begum
AU  - Mark Skehel
AU  - Andrew P. Carter
TI  - Shulin packages axonemal outer dynein arms for ciliary targeting
AID  - 10.1101/2020.09.04.282897
DP  - 2020 Jan 01
TA  - bioRxiv
PG  - 2020.09.04.282897
4099  - http://biorxiv.org/content/early/2020/09/04/2020.09.04.282897.short
4100  - http://biorxiv.org/content/early/2020/09/04/2020.09.04.282897.full
AB  - The main force generators in eukaryotic cilia and flagella are axonemal outer dynein arms (ODAs). During cilio-genesis, these ∼1.8 MDa complexes are assembled in the cytoplasm and targeted to cilia via an unknown mechanism. Here we use the ciliate Tetrahymena to identify two novel factors (Q22YU3 and Q22MS1) which bind ODAs in the cytoplasm and are required for their delivery to cilia. We show that Q22YU3, which we name Shulin, locks the ODA motor domains into a closed conformation and inhibits motor activity. Cryo-EM reveals how Shulin stabilizes this compact form of ODAs by binding to the dynein tails. Our findings provide a molecular explanation for how newly assembled dyneins are packaged for delivery to the cilia.Competing Interest StatementThe authors have declared no competing interest.