Wdr47, Camsaps, and Katanin cooperate to generate ciliary central microtubules

Abstract

The axonemal central pair (CP) are non-centrosomal microtubules critical for planar ciliary beat. How they form, however, is poorly understood. Here, we show that mammalian CP formation requires cooperative activities of Katanin, Camsaps, and Wdr47. Katanin severs peripheral microtubules to produce central microtubule seeds in nascent cilia. Camsaps stabilize minus ends of the seeds to facilitate MT outgrowth, whereas Wdr47 concentrates Camsaps into the axonemal central lumen to properly position the central microtubules. Wdr47 deficiency in mouse multicilia results in complete loss of CP, rotatory beat, and primary ciliary dyskinesia. Overexpression of Camsaps induces central microtubules in Wdr47-/- ependymal cells but at the expense of low efficiency, abnormal numbers, and wrong location, whereas overexpression of a dominant inhibitor of Katanin impairs the CP formation. We propose that Wdr47, Camsaps, and Katanin constitute a general cooperative work team for the generation of non-centrosomal MT arrays in polarized subcellular compartments.

Quantifying cilia beat frequency using high‐speed video microscopy: Assessing frame rate requirements when imaging different ciliated tissues

“…The easiest way to assess motile cilia function is by quantifying CBF via highspeed video microscopy (Francis & Lo, 2013;O'Callaghan et al, 2012;Sisson et al, 2003) and this forms a sizable chunk of the cilia literature. However, no standardized frame rate exists when imaging cilia motility for subsequent CBF calculation, this has resulted in a large range of frames rates used to image cilia motility within the published literature (Abdelhamed et al, 2018;Abdelhamed et al, 2020;Bustamante-Marin et al, 2019;Chen et al, 2016;Hagiwara et al, 2020;Hennessy et al, 1986;Liu et al, 2021; F I G U R E 3 Assessing how movie framerate influences CBF measurement accuracy for cilia beating between 0-15 Hz, as quantified by either manual counting or FFT-based algorithm (MATLAB). Cilia data from all tissues and temperatures that displayed reference CBFs between 0-15 Hz was pooled (n = 73) (reference CBF was calculated from 300 fps movies).…”

“…Our data matches previously published findings by highlighting the significant difference in CBF between airway and ependymal cilia and by emphasizing how CBF is modulated by changes in temperature. Murine ependymal cilia have been previously shown to beat significantly faster than airway cilia (Francis et al, 2009;Hagiwara et al, 2020;Mahuzier et al, 2018;Mikhailik et al, 2021), while increased incubation temperature is well recognized to result in a linear increase in mean CBF (Christopher et al, 2014;Schipor et al, 2006;Sisson et al, 2003;Welchering et al, 2015).…”

WDR47 facilitates ciliogenesis by modulating intraflagellar transport

“…We further demonstrated that WDR47/NMTN-1 ensures proper IFT particle movement and cargo delivery in the AWB neurons, promoting ciliogenesis. WDR47/NMTN-1 has been revealed as a microtubule-associated protein; it has been shown to interact with CAMSAP family proteins for microtubule-mediated processes (Chen, Zheng et al 2020, Buijs, Hummel et al 2021, Liu, Zheng et al 2021. In noncentrosomal microtubules, WDR47/NMTN-1 protects CAMSAP2 against kataninmediated severing and is required for axonal and dendritic development (Buijs, Hummel et al 2021).…”

“…In noncentrosomal microtubules, WDR47/NMTN-1 protects CAMSAP2 against kataninmediated severing and is required for axonal and dendritic development (Buijs, Hummel et al 2021). In mammalian multicilia, WDR47/NMTN-1 co-operates with CAMSAP family proteins and MT-severing enzyme katanin to generate ciliary central microtubules (Liu, Zheng et al 2021). WDR47/NMTN-1 also functions through CAMSAP3 to control neuronal migration and the early stages of neuronal polarization, which is important for neonatal mouse survival (Chen, Zheng et al 2020).…”

“…At least 17 different WDR proteins are associated with ciliopathies and majority of them have been identified as IFT components. One of the WDR proteins, WDR47 has been implicated in regulating formation of the central pair microtubules and ciliary beat in the motile cilia (Liu, Zheng et al 2021). However, its function in the primary cilia, such as the chemosensory neurons remains unknow.…”