The ciliary inner dynein arm, I1 dynein, is assembled in the cytoplasm and transported by IFT before axonemal docking. Issue 10 (30th October 2014)

• Record Type: Journal Article
• Authors: Viswanadha, Rasagnya; Hunter, Emily L.; Yamamoto, Ryosuke; Wirschell, Maureen; Alford, Lea M.; Dutcher, Susan K.; Sale, Winfield S.
• Is Part Of: Cytoskeleton. Volume 71:Issue 10(2014:Oct.)
• Page Start: 573
• Page End: 586
• Publication Date: 2014-10-30
• Subjects: Cytoskeleton -- Periodicals; 571.65405
• DOI: 10.1002/cm.21192
• Languages: English
• ISSNs: 1949-3584

Abstract

<abstract abstract-type="main"> <title> <x xml:space="preserve">Abstract</x> </title> <p>To determine mechanisms of assembly of ciliary dyneins, we focused on the <italic>Chlamydomonas</italic> inner dynein arm, I1 dynein, also known as dynein f. I1 dynein assembles in the cytoplasm as a 20S complex similar to the 20S I1 dynein complex isolated from the axoneme. The intermediate chain subunit, IC140 (<italic>IDA7</italic>), and heavy chains (<italic>IDA1, IDA2</italic>) are required for 20S I1 dynein preassembly in the cytoplasm. Unlike I1 dynein derived from the axoneme, the cytoplasmic 20S I1 complex will not rebind I1‐deficient axonemes <italic>in vitro</italic>. To test the hypothesis that I1 dynein is transported to the distal tip of the cilia for assembly in the axoneme, we performed cytoplasmic complementation in dikaryons formed between wild‐type and I1 dynein mutant cells. Rescue of I1 dynein assembly in mutant cilia occurred first at the distal tip and then proceeded toward the proximal axoneme. Notably, in contrast to other combinations, I1 dynein assembly was significantly delayed in dikaryons formed between <italic>ida7</italic> and <italic>ida3</italic>. Furthermore, rescue of I1 dynein assembly required new protein synthesis in the <italic>ida7 × ida3</italic> dikaryons. On the basis of the additional observations, we postulate that IDA3 is required for 20S I1 dynein transport. Cytoplasmic complementation in dikaryons using the conditional kinesin‐2 mutant, <italic>fla10‐1</italic> revealed that transport of I1 dynein is dependent on kinesin‐2 activity. Thus, I1 dynein complex assembly depends upon IFT for transport to the ciliary distal tip prior to docking in the axoneme. © 2014 Wiley Periodicals, Inc.</p> </abstract>