An evolutionary balance: conservation vs innovation in ciliate membrane trafficking. (27th October 2016)

• Record Type: Journal Article
• Authors: Guerrier, Sabrice; Plattner, Helmut; Richardson, Elisabeth; Dacks, Joel B.; Turkewitz, Aaron P.
• Is Part Of: Traffic. Volume 18:Number 1(2017)
• Page Start: 18
• Page End: 28
• Publication Date: 2016-10-27
• Subjects: Alveolate -- autophagy -- calcium signaling -- nucleophagy -- Rab GTPase -- SNARE -- vesicles; Biological transport -- Periodicals; 571.6
• DOI: 10.1111/tra.12450
• Languages: English
• ISSNs: 1398-9219

Abstract

Abstract : As most of eukaryotic diversity lies in single‐celled protists, they represent unique opportunities to ask questions about the balance of conservation and innovation in cell biological features. Among free‐living protists the ciliates offer ease of culturing, a rich array of experimental approaches, and versatile molecular tools, particularly in Tetrahymena thermophila and Paramecium tetraurelia . These attributes have been exploited by researchers to analyze a wealth of cellular structures in these large and complex cells. This mini‐review focuses on 3 aspects of ciliate membrane dynamics, all linked with endolysosomal trafficking. First is nutrition based on phagocytosis and maturation of food vacuoles. Secondly, we discuss regulated exocytosis from vesicles that have features of both dense core secretory granules but also lysosome‐related organelles. The third topic is the targeting, breakdown and resorption of parental nuclei in mating partners. For all 3 phenomena, it is clear that elements of the canonical membrane‐trafficking system have been retained and in some cases repurposed. In addition, there is evidence that recently evolved, lineage‐specific proteins provide determinants in these pathways. Abstract : Several species of ciliates represent useful experiment organisms for cell biology research, and particularly for analyzing the outcomes of evolutionary trajectories that are distant from those of fungi or animals. This review focuses on 3 phenomena in ciliates that are all related to conserved pathways of endolysosomal trafficking, but with unique ciliate features: phagosome formation and maturation, regulated exocytosis of secretory granules, and programmed degradation of specific nuclei during conjugation.