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Review ARTICLE Provisionally accepted The full-text will be published soon. Notify me

Front. Cell Dev. Biol. | doi: 10.3389/fcell.2019.00292

Emerging roles of the intraflagellar transport system in the orchestration of cellular degradation pathways

  • 1Department of Life Sciences, University of Siena, Italy
  • 2Department of Life Sciences, University of Siena, Italy

Ciliated cells exploit a specific transport system, namely the intraflagellar transport (IFT) system, to ensure the traffic of molecules from the cell body to the cilium. However, it is now clear that IFT activity is not restricted to cilia-related functions. This is strikingly exemplified by the observation that IFT proteins play important roles in cells lacking a primary cilium, such as lymphocytes. Indeed, in T cells the IFT system regulates the polarized transport of endosome-associated T cell antigen receptors and signaling mediators during assembly of the immune synapse, a specialized interface that forms on encounter with a cognate antigen presenting cell and on which T cell activation and effector function crucially depend. Cellular degradation pathways have recently emerged as new extraciliary functions of the IFT system. IFT proteins have been demonstrated to regulate autophagy in ciliated cells through their ability to recruit the autophagy machinery to the base of the cilium. We have now implicated the IFT component IFT20 in another central degradation process that also controls the latest steps in autophagy, namely lysosome function, by regulating the cation-independent mannose-6-phosphate receptor (CI-MPR)-dependent lysosomal targeting of acid hydrolases. This involves the ability of IFT20 to act as adaptor coupling the CI-MPR to dynein for retrograde transport to the trans-Golgi network. In this short review we will discuss the emerging roles of IFT proteins in cellular degradation pathways.

Keywords: intraflagellar transport, T ceil, degradation pathways, Autopaghy, Lysosome

Received: 07 Aug 2019; Accepted: 06 Nov 2019.

Copyright: © 2019 Finetti, Capitani and Baldari. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence:
Dr. Francesca Finetti, Department of Life Sciences, University of Siena, Siena, 53100, Tuscany, Italy, finetti4@unisi.it
Prof. Cosima T. Baldari, University of Siena, Department of Life Sciences, Siena, 53100, Italy, cosima.baldari@unisi.it