Membrane Dynamics at the Nuclear Exchange Junction during Early Mating (One to Four Hours) in the Ciliate Tetrahymena thermophila

Cole, Elliot; Giddings, Thomas H.; Ozzello, Courtney; Winey, Mark; O’Toole, Eileen; Orias, J D; Hamilton, Eileen P.; Guerrier, Sabrice; Ballard, Anna; Aronstein, Tyler

doi:10.1128/ec.00164-14

Cited by 16 publications

(25 citation statements)

References 44 publications

(47 reference statements)

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“…ESCRT complexes are best known for their role in protein degradation at the multivesicular body (MVB) and functional MVBs have been identified in Tetrahymena which also possesses only Vps23 as its ESCRT I (Leung et al. 2008; Cole et al. 2015).…”

Section: Resultsmentioning

confidence: 99%

The Oxymonad Genome Displays Canonical Eukaryotic Complexity in the Absence of a Mitochondrion

Karnkowska

Treitli

Brzoň

et al. 2019

Molecular Biology and Evolution

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The discovery that the protist Monocercomonoides exilis completely lacks mitochondria demonstrates that these organelles are not absolutely essential to eukaryotic cells. However, the degree to which the metabolism and cellular systems of this organism have adapted to the loss of mitochondria is unknown. Here, we report an extensive analysis of the M. exilis genome to address this question. Unexpectedly, we find that M. exilis genome structure and content is similar in complexity to other eukaryotes and less “reduced” than genomes of some other protists from the Metamonada group to which it belongs. Furthermore, the predicted cytoskeletal systems, the organization of endomembrane systems, and biosynthetic pathways also display canonical eukaryotic complexity. The only apparent preadaptation that permitted the loss of mitochondria was the acquisition of the SUF system for Fe–S cluster assembly and the loss of glycine cleavage system. Changes in other systems, including in amino acid metabolism and oxidative stress response, were coincident with the loss of mitochondria but are likely adaptations to the microaerophilic and endobiotic niche rather than the mitochondrial loss per se. Apart from the lack of mitochondria and peroxisomes, we show that M. exilis is a fully elaborated eukaryotic cell that is a promising model system in which eukaryotic cell biology can be investigated in the absence of mitochondria.

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Section: Resultsmentioning

confidence: 99%

The Oxymonad Genome Displays Canonical Eukaryotic Complexity in the Absence of a Mitochondrion

Karnkowska

Treitli

Brzoň

et al. 2019

Molecular Biology and Evolution

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“…Notably, however, VPS23 is retained in some diplomonads and is characterized by the presence of a UEV domain which is required for interaction with cargo tagged with Ubiquitin for targeted lysosomal degradation. Lineages such as Tetrahymena , Entamoeba , and Monocercomonoides conserving only the VPS23 from ESCRT-I appear to be capable of forming functional (or at least morphologically identifiable) multivesicular bodies (Cole et. al., 2015, Okada et.…”

Section: Discussionmentioning

confidence: 99%

Unexpected organellar locations of ESCRT machinery in Giardia intestinalis and complex evolutionary dynamics spanning the transition to parasitism in the lineage Fornicata

Pipaliya

Santos

Salas‐Leiva

et al. 2021

Preprint

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Comparing a parasitic lineage to its free-living relatives is a powerful way to understand how the evolutionary transition to parasitism occurred. Giardia intestinalis (Fornicata) is a leading cause of gastrointestinal disease world-wide and is famous for its unusual complement of cellular compartments, such as having peripheral vacuoles instead of typical endosomal compartments. Endocytosis plays an important role in Giardia's pathogenesis. Endosomal sorting complexes required for transport (ESCRT) are membrane-deforming proteins associated with the late endosome/multivesicular body (MVB). MVBs are ill-defined in G. intestinalis and roles for identified ESCRT-related proteins are not fully understood in the context of its unique endocytic system. Furthermore, components thought to be required for full ESCRT functionality have not yet been documented in this species. We used genomic and transcriptomic data from several Fornicata species to clarify the evolutionary genome streamlining observed in Giardia, as well as to detect any divergent orthologs of the Fornicata ESCRT subunits. We observed differences in the ESCRT machinery complement between Giardia strains. Microscopy-based investigations of key components of ESCRT machinery such as GiVPS36and GiVPS25 link them to peripheral vacuoles, highlighting these organelles as simplified MVB equivalents. Unexpectedly, we show ESCRT components associated with the Endoplasmic Reticulum, and for the first time, mitosomes. Finally, we identified the rare ESCRT component CHMP7 in several fornicate representatives, including Giardia, and show that contrary to current understanding, CHMP7 evolved from a gene fusion of VPS25 and SNF7 domains, prior to the last eukaryotic common ancestor, over 1.5 billion years ago. Our findings show that ESCRT machinery in G. intestinalis is far more varied and complete than previously thought, and associating to multiple cellular locations and presenting changes in ESCRT complement which pre-date adoption of a parasitic lifestyle.

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“…Moreover, during pronuclear exchange, a hemispherical meshwork of microtubules is formed and associates with each migratory pronucleus (Cole ; Cole et al. ; Orias et al. ).…”

Section: Discussionmentioning

confidence: 99%

Role of the Cytosolic Heat Shock Protein 70 Ssa5 in the Ciliate Protozoan Tetrahymena thermophila

Fukuda

Akematsu

Attiq

et al. 2015

J Eukaryotic Microbiology

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Heat shock protein 70 (Hsp70) is a member of a family of conserved chaperone proteins whose function is well investigated in many model organisms. Here we focus on an Hsp70 called Ssa5 in the ciliate protozoan Tetrahymena thermophila, and reveal that its translation is heat inducible as for general Hsps. Moreover, the protein is abundantly expressed in the cytoplasm during sexual reproduction (conjugation) as well as in response to heat-stress. Knocking out of SSA5 (ΔSSA5) does not affect the survival of the cell under heat-stress, likely due to other Hsp70 paralogs compensating for the defect. During conjugation, ΔSSA5 leads to a fertilization defect in which the two pronuclei are in close proximity but never fuse. The unfertilized pronuclei differentiate, resulting in a heterokaryon with developed haploid germline and somatic nuclei. In addition, degeneration of the parental somatic nucleus is not affected. These results suggest a specific involvement of Ssa5 in pronuclear fusion and fertilization.

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Membrane Dynamics at the Nuclear Exchange Junction during Early Mating (One to Four Hours) in the Ciliate Tetrahymena thermophila

Cited by 16 publications

References 44 publications

The Oxymonad Genome Displays Canonical Eukaryotic Complexity in the Absence of a Mitochondrion

The Oxymonad Genome Displays Canonical Eukaryotic Complexity in the Absence of a Mitochondrion

Unexpected organellar locations of ESCRT machinery in Giardia intestinalis and complex evolutionary dynamics spanning the transition to parasitism in the lineage Fornicata

Role of the Cytosolic Heat Shock Protein 70 Ssa5 in the Ciliate Protozoan Tetrahymena thermophila

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