The Enigmatic Role of Lipids in Cilia Signaling.

Inna V Nechipurenko

doi:10.3389/fcell.2020.00777

Inna V Nechipurenko

Open Access

https://doi.org/10.3389/fcell.2020.00777

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Abstract

Primary cilia are specialized cellular structures that project from the surface of most cell types in metazoans and mediate transduction of major signaling pathways. The ciliary membrane is contiguous with the plasma membrane, yet it exhibits distinct protein and lipid composition, which is essential for ciliary function. Diffusion barriers at the base of a cilium are responsible for establishing unique molecular composition of this organelle. Although considerable progress has been made in identifying mechanisms of ciliary protein trafficking in and out of cilia, it remains largely unknown how the distinct lipid identity of the ciliary membrane is achieved. In this mini review, I summarize recent developments in characterizing lipid composition and organization of the ciliary membrane and discuss the emerging roles of lipids in modulating activity of ciliary signaling components including ion channels and G protein-coupled receptors.

Highlights

Cilia are hair-like cellular projections that are highly conserved across eukaryotes (Carvalho-Santos et al, 2011)
To fully understand how ciliary phospholipid composition is modulated by these enzymes in different contexts, and how it contributes to cilia-mediated cellular functions
In further support of the raft-like composition of ciliary membranes, the transition zone (TZ) membrane in Chlamydomonas reinhardtii is exceptionally resistant to detergent extraction, and Laurdan microscopy of T. brucei and Madin–Darby Canine Kidney (MDCK) cells showed condensed lipid microdomains in the trypanosome flagella and at the base of primary cilia (Kamiya and Witman, 1984; Vieira et al, 2006; Tyler et al, 2009)

Summary

Introduction

Cilia (or flagella) are hair-like cellular projections that are highly conserved across eukaryotes (Carvalho-Santos et al, 2011). To fully understand how ciliary phospholipid composition is modulated by these enzymes in different contexts, and how it contributes to cilia-mediated cellular functions. Catalytic activity of Inpp5e is required for proper localization of TZ proteins and Septin2; it is likely that Inpp5e-modulated PPI composition at the cilia base can dynamically regulate TZ assembly.

Results

Conclusion