ERICH3 in Primary Cilia Regulates Cilium Formation and the Localisations of Ciliary Transport and Sonic Hedgehog Signaling Proteins

Abstract

Intraflagellar transport (IFT) is essential for the formation and function of the microtubule-based primary cilium, which acts as a sensory and signalling device at the cell surface. Consisting of IFT-A/B and BBSome cargo adaptors that associate with molecular motors, IFT transports protein into (anterograde IFT) and out of (retrograde IFT) the cilium. In this study, we identify the mostly uncharacterised ERICH3 protein as a component of the mammalian primary cilium. Loss of ERICH3 causes abnormally short cilia and results in the accumulation of IFT-A/B proteins at the ciliary tip, together with reduced ciliary levels of retrograde transport regulators, ARL13B, INPP5E and BBS5. We also show that ERICH3 ciliary localisations require ARL13B and BBSome components. Finally, ERICH3 loss causes positive (Smoothened) and negative (GPR161) regulators of sonic hedgehog signaling (Shh) to accumulate at abnormally high levels in the cilia of pathway-stimulated cells. Together, these findings identify ERICH3 as a novel component of the primary cilium that regulates cilium length and the ciliary levels of Shh signaling molecules. We propose that ERICH3 functions within retrograde IFT-associated pathways to remove signaling proteins from cilia.

Targeting Wnt/tenascin C-mediated cross talk between pancreatic cancer cells and stellate cells via activation of the metastasis suppressor NDRG1

“…4 , S3 and S4 ), but also the PSCs ( Fig. 5 A ), where these proteins are involved in PSC activation ( 102 , 103 ).…”

A primary cilium in oligodendrocytes: a fine structure signal of repairs in thalamic Osmotic Demyelination Syndrome (ODS)

“…These intracellular CAV vesicles cannot be dispatched to the plasmalemma surface because either the restrained space caused by crowding of the neuropil and neighboring macroglia and nerve cell bodies for a final outwardly exhibition or because the 'program' for building has been arrested due to reestablishment of differentiation, as seen at the 36-hour stage afterward. A peculiar intracellular furrow surrounding the tip of a centriole noted in, [190][191][192][193][194][195][196] is similar to typical cilium, with a microtubule alignment fascicle bearing these adjacent CAV aka 'IFT' vesicles distributed with small size and eventually lined to build the cilium shaft and envelopment. [180][181][182][183][184][185][186] The shaft and pocket membrane contained heterogeneous electron dense fuzzy membrane or cargo content, as the ciliary membrane either building or retrieving and recycling 'old' parts by autophagocytosis.…”

“…174,179,180 This finding would comfort other data where arl13b protein would associate with regrowth and strongly underlined the axon hillocks reestablishment of microtubule network. 182,[187][188][189][190][191][192][193][194][195][196] One can now imply and consider that a progressive process of post ODS has been initiated, healing the myelinolytic zone, as soon as the restoration of osmotic [Na+] was made. This healing process can also be supported by some replicating events that were revealed as cell cycle mitosis got detected for some oligodendrocytes and reentry into interphase with resulted 'twin' poorly differentiated cells.…”

ERK pathway activation inhibits ciliogenesis and causes defects in motor behavior, ciliary gating, and cytoskeletal rearrangement

“…RPE1 cilium staining: Staining was performed according to Alsolami et al, 2019. Cells were seeded on chamber slides and grown to 80% confluency before serum starving in DMEM with 0.5% FBS for 48 hours.…”

“…Secondary antibody (Alexa Fluor 488 goat anti-mouse IgG, Invitrogen, A11001) was diluted in PBX (1:500) and added to coverslips for 1 hour at room temp. Slides were washed 3x5 minutes in PBS, mounted with Flouromount G, and imaged with 60x and 100x oil immersion objectives on the spinning disk confocal (Alsolami et al, 2019).…”