TABLE 1.

Microscopic analysis revealed the presence of (A) cilia deformations (e.g., bulb at the tip, membrane bud); (B) vesicles or vesicle-like structures associated with cilia (C) ciliary EVs generated at the ciliary tip (D) alongside the axoneme, or (E) the ciliary base.

Source of ciliary EVs		Cilia	Models	EV markers	Imaging techniques	References
(A) Vesicular structures associated with cilia		PC	Mouse neuroepithelial cells	Prominin-1	TEM	Dubreuil et al. (2007)
		PC	Inpp5eΔ/Δ cells lining a mouse kidney cyst	-	TEM	Jacoby et al. (2009)
		PC	RPE-hTERT	Smo	FBM	Huang et al. (2016)
		PC	Prom1 K138Q mutation in MDCK cells	Prominin-1	SEM	Singer et al. (2019)
(B) Vesicles associated with cilia		PC	Pkhd1del2/del2 mouse cholangiocyte	-	TEM	Woollard et al. (2007)
		PC	Pkhd1del2/del2 and WT mouse cholangiocyte	Polycystin 1	TEM	Hogan et al. (2009)
		PC	IMCD-3 and rat biliary epithelial cells	PKD proteins	SEM
		PC	PCK rat cholongiocyte, WT and Pkhd1del2/del2 mouse cholangiocyte	-	SEM, TEM	Masyuk et al. (2010)
		PC	MEF	-	SEM	Pampliega et al. (2013)
		PC	MDCK	Smo, Sec10	FBM	Chacon-Heszele et al. (2014)
		MC	Turtle ductuli efferentes epithelial cells	-	TEM	Tarique et al. (2019)
		PC	MDCK-II	-	Cryo-ET	Kiesel et al. (2020)
(C) Ciliary EV released at the cilia tip		MC	Chlamydomonas reinhardtii	-	Cryo-EM, SEM	Bergman et al. (1975)
		MC	Chlamydomonas reinhardtii, Chlamydomonas moewusii strain cc957	VLE protease	TEM, DICM	Wood et al. (2013)
		PC	RPE1	CEP162	SEM, FBM	Wang et al. (2013)
		PC	C. elegans WT and mutants	LOV-1, PKD-2	TEM, ET	Wang et al. (2014)
				PKD-2	TEM, FBM	Maguire et al. (2015)
				PKD-2	TEM, ET, FBM	O’Hagan et al. (2017)
		MC	Chlamydomonas reinhardtii	-	TEM	Dentler, (2013)
						Cao et al. (2015)
		MC	Chlamydomonas WT and mutant strains	PDCD6	FBM	Long et al. (2016)
		PC	Arl6−/− IMCD-3, β-arrestin2−/− mIMCD-3	GPCRs	FBM	Nager et al. (2017)
		PC	NIH/3T3, mIMCD-3, hTERT RPE-1, Inpp5e−/− and Inpp5e+/- MEF	Arl13b, 5HT6	FBM	Phua et al. (2017)
		PC	Patient-derived glioblastoma cells	Arl13b	FBM	Hoang-Minh et al. (2018)
		PC	RPE1	Smo	FBM	Wang et al. (2019)
		PC	ICK-KO hTERT-RPE-1	Arl13b, IFT88	FBM	Nakamura et al. (2020)
		PC	C. elegans WT and mutants	PKD-2, CIL-7	TEM, ET, FBM	Akella et al. (2020)
				TSP-6, TSP-7	FBM	Razzauti and Laurent, (2021)
( D ) Ciliary EV released alongside the axoneme		MC	Trypanosoma brucei	-	TEM, FBM, DICM	Szempruch et al. (2016b)
		PC	Rds−/− mouse	-	TEM	Salinas et al. (2017)
		PC	Kidney cell lines	-	ET	Sun et al. (2019)
( E ) Ciliary EV released at the ciliary base		MC	Chlamydomonas WT and mutant strains	Flagellar membrane glycoproteins	FBM	Bloodgood et al. (1986)
		PC	C. elegans WT and mutants	LOV-1, PKD-2, CIL-7	TEM, ET	Wang et al., 2014, 2021a
				PKD-2, CIL-7	TEM, ET, FBM	Silva et al. (2017)
						Akella et al. (2020)
				TSP-6, TSP-7	FBM	Razzauti and Laurent, (2021)

PC, primary cilia; MC, motile cilia; WT, wild-type; PCK, rat model of polycystic kidney disease; mIMCD-3, mouse inner medullary collecting duct-3; MEF, mouse embryonic fibroblast; NIH/3T3, fibroblast cell line that was isolated from a mouse NIH/Swiss embryo; hTERT RPE-1, human telomerase reverse transcriptase immortalized retinal pigment epithelial cell; MDCK, Madin-Darby canine kidney cells; DICM, differential interference contrast microscopy; TEM, transmission electron microscopy; SEM, scanning electron microscope; FBM, fluorescence-based microscopy; ET, electron tomography; Cryo-EM, cryogenic electron microscopy; Cryo-ET, cryo-electron tomography.