Tctex-1 controls ciliary resorption by regulating branched actin polymerization and endocytosis.

TitleTctex-1 controls ciliary resorption by regulating branched actin polymerization and endocytosis.
Publication TypeJournal Article
Year of Publication2017
AuthorsSaito M, Otsu W, Hsu K-S, Chuang J-Z, Yanagisawa T, Shieh V, Kaitsuka T, Wei F-Y, Tomizawa K, Sung C-H
JournalEMBO Rep
Volume18
Issue8
Pagination1460-1472
Date Published2017 08
ISSN1469-3178
KeywordsActins, Cell Line, Cilia, Clathrin, Dynamins, Dyneins, Endocytosis, Epithelial Cells, Humans, Phosphorylation, Protein Multimerization, Retina
Abstract

The primary cilium is a plasma membrane-protruding sensory organelle that undergoes regulated assembly and resorption. While the assembly process has been studied extensively, the cellular machinery that governs ciliary resorption is less well understood. Previous studies showed that the ciliary pocket membrane is an actin-rich, endocytosis-active periciliary subdomain. Furthermore, Tctex-1, originally identified as a cytoplasmic dynein light chain, has a dynein-independent role in ciliary resorption upon phosphorylation at Thr94. Here, we show that the remodeling and endocytosis of the ciliary pocket membrane are accelerated during ciliary resorption. This process depends on phospho(T94)Tctex-1, actin, and dynamin. Mechanistically, Tctex-1 physically and functionally interacts with the actin dynamics regulators annexin A2, Arp2/3 complex, and Cdc42. Phospho(T94)Tctex-1 is required for Cdc42 activation before the onset of ciliary resorption. Moreover, inhibiting clathrin-dependent endocytosis or suppressing Rab5GTPase on early endosomes effectively abrogates ciliary resorption. Taken together with the epistasis functional assays, our results support a model in which phospho(T94)Tctex-1-regulated actin polymerization and periciliary endocytosis play an active role in orchestrating the initial phase of ciliary resorption.

DOI10.15252/embr.201744204
Alternate JournalEMBO Rep.
PubMed ID28607034
PubMed Central IDPMC5538770
Grant ListR01 EY011307 / EY / NEI NIH HHS / United States
R01 EY016805 / EY / NEI NIH HHS / United States