Eukaryotic CellPub Date : 2015-06-01Epub Date: 2015-03-27DOI: 10.1128/EC.00276-14
Joachim M Matz, Alyssa Ingmundson, Jean Costa Nunes, Werner Stenzel, Kai Matuschewski, Taco W A Kooij
{"title":"In Vivo Function of PTEX88 in Malaria Parasite Sequestration and Virulence.","authors":"Joachim M Matz, Alyssa Ingmundson, Jean Costa Nunes, Werner Stenzel, Kai Matuschewski, Taco W A Kooij","doi":"10.1128/EC.00276-14","DOIUrl":"https://doi.org/10.1128/EC.00276-14","url":null,"abstract":"<p><p>Malaria pathology is linked to remodeling of red blood cells by eukaryotic Plasmodium parasites. Central to host cell refurbishment is the trafficking of parasite-encoded virulence factors through the Plasmodium translocon of exported proteins (PTEX). Much of our understanding of its function is based on experimental work with cultured Plasmodium falciparum, yet direct consequences of PTEX impairment during an infection remain poorly defined. Using the murine malaria model parasite Plasmodium berghei, it is shown here that efficient sequestration to the pulmonary, adipose, and brain tissue vasculature is dependent on the PTEX components thioredoxin 2 (TRX2) and PTEX88. While TRX2-deficient parasites remain virulent, PTEX88-deficient parasites no longer sequester in the brain, correlating with abolishment of cerebral complications in infected mice. However, an apparent trade-off for virulence attenuation was spleen enlargement, which correlates with a strongly reduced schizont-to-ring-stage transition. Strikingly, general protein export is unaffected in PTEX88-deficient mutants that mature normally in vitro. Thus, PTEX88 is pivotal for tissue sequestration in vivo, parasite virulence, and preventing exacerbation of spleen pathology, but these functions do not correlate with general protein export to the host erythrocyte. The presented data suggest that the protein export machinery of Plasmodium parasites and their underlying mechanistic features are considerably more complex than previously anticipated and indicate challenges for targeted intervention strategies. </p>","PeriodicalId":11891,"journal":{"name":"Eukaryotic Cell","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2015-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1128/EC.00276-14","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"33170248","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Eukaryotic CellPub Date : 2015-06-01Epub Date: 2015-04-10DOI: 10.1128/EC.00002-15
Zhiyun Guan, Haoping Liu
{"title":"Overlapping Functions between SWR1 Deletion and H3K56 Acetylation in Candida albicans.","authors":"Zhiyun Guan, Haoping Liu","doi":"10.1128/EC.00002-15","DOIUrl":"https://doi.org/10.1128/EC.00002-15","url":null,"abstract":"<p><p>Nucleosome destabilization by histone variants and modifications has been implicated in the epigenetic regulation of gene expression, with the histone variant H2A.Z and acetylation of H3K56 (H3K56ac) being two examples. Here we find that deletion of SWR1, the major subunit of the SWR1 complex depositing H2A.Z into chromatin in exchange for H2A, promotes epigenetic white-opaque switching in Candida albicans. We demonstrate through nucleosome mapping that SWR1 is required for proper nucleosome positioning on the promoter of WOR1, the master regulator of switching, and that its effects differ in white and opaque cells. Furthermore, we find that H2A.Z is enriched adjacent to nucleosome-free regions at the WOR1 promoter in white cells, suggesting a role in the stabilization of a repressive chromatin state. Deletion of YNG2, a subunit of the NuA4 H4 histone acetyltransferase (HAT) that targets SWR1 activity through histone acetylation, produces a switching phenotype similar to that of swr1, and both may act downstream of the GlcNAc signaling pathway. We further uncovered a genetic interaction between swr1 and elevated H3K56ac with the discovery that the swr1 deletion mutant is highly sensitive to nicotinamide. Our results suggest that the interaction of H2A.Z and H3K56ac regulates epigenetic switching at the nucleosome level, as well as having global effects. </p>","PeriodicalId":11891,"journal":{"name":"Eukaryotic Cell","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2015-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1128/EC.00002-15","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"33206020","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Eukaryotic CellPub Date : 2015-06-01Epub Date: 2015-04-03DOI: 10.1128/EC.00033-15
Geovani López, Héctor Quezada, Mariana Duhne, James González, Mijail Lezama, Mohammed El-Hafidi, Maritrini Colón, Ximena Martínez de la Escalera, Mirelle Citlali Flores-Villegas, Claudio Scazzocchio, Alexander DeLuna, Alicia González
{"title":"Diversification of Paralogous α-Isopropylmalate Synthases by Modulation of Feedback Control and Hetero-Oligomerization in Saccharomyces cerevisiae.","authors":"Geovani López, Héctor Quezada, Mariana Duhne, James González, Mijail Lezama, Mohammed El-Hafidi, Maritrini Colón, Ximena Martínez de la Escalera, Mirelle Citlali Flores-Villegas, Claudio Scazzocchio, Alexander DeLuna, Alicia González","doi":"10.1128/EC.00033-15","DOIUrl":"https://doi.org/10.1128/EC.00033-15","url":null,"abstract":"<p><p>Production of α-isopropylmalate (α-IPM) is critical for leucine biosynthesis and for the global control of metabolism. The budding yeast Saccharomyces cerevisiae has two paralogous genes, LEU4 and LEU9, that encode α-IPM synthase (α-IPMS) isozymes. Little is known about the biochemical differences between these two α-IPMS isoenzymes. Here, we show that the Leu4 homodimer is a leucine-sensitive isoform, while the Leu9 homodimer is resistant to such feedback inhibition. The leu4Δ mutant, which expresses only the feedback-resistant Leu9 homodimer, grows slowly with either glucose or ethanol and accumulates elevated pools of leucine; this phenotype is alleviated by the addition of leucine. Transformation of the leu4Δ mutant with a centromeric plasmid carrying LEU4 restored the wild-type phenotype. Bimolecular fluorescent complementation analysis showed that Leu4-Leu9 heterodimeric isozymes are formed in vivo. Purification and kinetic analysis showed that the hetero-oligomeric isozyme has a distinct leucine sensitivity behavior. Determination of α-IPMS activity in ethanol-grown cultures showed that α-IPM biosynthesis and growth under these respiratory conditions depend on the feedback-sensitive Leu4 homodimer. We conclude that retention and further diversification of two yeast α-IPMSs have resulted in a specific regulatory system that controls the leucine-α-IPM biosynthetic pathway by selective feedback sensitivity of homomeric and heterodimeric isoforms. </p>","PeriodicalId":11891,"journal":{"name":"Eukaryotic Cell","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2015-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1128/EC.00033-15","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"33063542","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Eukaryotic CellPub Date : 2015-06-01Epub Date: 2015-04-17DOI: 10.1128/EC.00018-15
Bert-Ewald Priegnitz, Ulrike Brandt, Khomaizon A K Pahirulzaman, Jeroen S Dickschat, André Fleißner
{"title":"The AngFus3 Mitogen-Activated Protein Kinase Controls Hyphal Differentiation and Secondary Metabolism in Aspergillus niger.","authors":"Bert-Ewald Priegnitz, Ulrike Brandt, Khomaizon A K Pahirulzaman, Jeroen S Dickschat, André Fleißner","doi":"10.1128/EC.00018-15","DOIUrl":"https://doi.org/10.1128/EC.00018-15","url":null,"abstract":"<p><p>Adaptation to a changing environment is essential for the survival and propagation of sessile organisms, such as plants or fungi. Filamentous fungi commonly respond to a worsening of their growth conditions by differentiation of asexually or sexually produced spores. The formation of these specialized cell types is, however, also triggered as part of the general life cycle by hyphal age or density. Spores typically serve for dispersal and, therefore, translocation but can also act as resting states to endure times of scarcity. Eukaryotic differentiation in response to environmental and self-derived signals is commonly mediated by three-tiered mitogen-activated protein (MAP) kinase signaling cascades. Here, we report that the MAP kinase Fus3 of the black mold Aspergillus niger (AngFus3) and its upstream kinase AngSte7 control vegetative spore formation and secondary metabolism. Mutants lacking these kinases are defective in conidium induction in response to hyphal density but are fully competent in starvation-induced sporulation, indicating that conidiation in A. niger is triggered by various independent signals. In addition, the mutants exhibit an altered profile of volatile metabolites and secrete dark pigments into the growth medium, suggesting a dysregulation of the secondary metabolism. By assigning the AngFus3 MAP kinase pathway to the transduction of a potentially self-derived trigger, this work contributes to the unraveling of the intricate signaling networks controlling fungal differentiation. Moreover, our data further support earlier observations that differentiation and secondary metabolism are tightly linked in filamentous fungi. </p>","PeriodicalId":11891,"journal":{"name":"Eukaryotic Cell","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2015-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1128/EC.00018-15","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"33229474","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Eukaryotic CellPub Date : 2015-06-01DOI: 10.1128/EC.00075-15
{"title":"Articles of Significant Interest Selected from This Issue by the Editors","authors":"","doi":"10.1128/EC.00075-15","DOIUrl":"https://doi.org/10.1128/EC.00075-15","url":null,"abstract":"Histone variants and modifications are linked to epigenetic regulation of gene expression through altering nucleosome dynamics and stability. Guan and Liu (p. 578 –587) show that deposition of the histone variant H2A.Z by the chromatin remodeling complex SWR1 regulates switching between the white and opaque epigenetic states in Candida albicans. Deletion of SWR1 promotes the opaque state. SWR1 affects differential nucleosome positioning between the white and opaque states on the promoter of WOR1, the master regulator of switching. H2A.Z enrichment in this region in white cells suggests its role in establishing a repressive chromatin state. Finally, the authors demonstrate a synthetic lethal interaction between swr1 and H3K56 acetylation, which also promotes the opaque state. Their findings identify a novel genetic interaction between swr1 and H3K56 acetylation with implications for epigenetic regulation on the level of nucleosome dynamics and stability.","PeriodicalId":11891,"journal":{"name":"Eukaryotic Cell","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2015-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83735077","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Eukaryotic CellPub Date : 2015-05-01DOI: 10.1128/ec.00059-15
{"title":"Article of Significant Interest Selected from This Issue by the Editors","authors":"","doi":"10.1128/ec.00059-15","DOIUrl":"https://doi.org/10.1128/ec.00059-15","url":null,"abstract":"Mechanisms of Increased Susceptibility to Salmonella enterica Serovar Typhimurium Bacteremia in the Context of Malaria in African Children Salmonella enterica serovar Typhimurium bacteremia is known to be associated with malaria in African children. To understand the immunological basis of this association, Nyirenda et al. (e00057-17) investigated bactericidal immunity to S . Typhimurium in children with acute and convalescent uncomplicated malaria and in controls. They found that Plas-modium falciparum infection reduced serum bactericidal activity to S . Typhimurium and was associated with reduced complement C3, irrespective of preexisting specific-IgG antibody titers. P. falciparum infection also reduced whole-blood bactericidal activity to S . Typhimurium and was associated with reduction of neutrophil respiratory burst. These findings provide new insights into the increase in susceptibility to S . Typhimurium bacteremia in children from settings of malaria endemicity.","PeriodicalId":11891,"journal":{"name":"Eukaryotic Cell","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2015-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80741431","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Eukaryotic CellPub Date : 2015-05-01Epub Date: 2015-03-06DOI: 10.1128/EC.00011-15
S D Willger, Z Liu, R A Olarte, M E Adamo, J E Stajich, L C Myers, A N Kettenbach, D A Hogan
{"title":"Analysis of the Candida albicans Phosphoproteome.","authors":"S D Willger, Z Liu, R A Olarte, M E Adamo, J E Stajich, L C Myers, A N Kettenbach, D A Hogan","doi":"10.1128/EC.00011-15","DOIUrl":"https://doi.org/10.1128/EC.00011-15","url":null,"abstract":"<p><p>Candida albicans is an important human fungal pathogen in both immunocompetent and immunocompromised individuals. C. albicans regulation has been studied in many contexts, including morphological transitions, mating competence, biofilm formation, stress resistance, and cell wall synthesis. Analysis of kinase- and phosphatase-deficient mutants has made it clear that protein phosphorylation plays an important role in the regulation of these pathways. In this study, to further our understanding of phosphorylation in C. albicans regulation, we performed a deep analysis of the phosphoproteome in C. albicans. We identified 19,590 unique peptides that corresponded to 15,906 unique phosphosites on 2,896 proteins. The ratios of serine, threonine, and tyrosine phosphosites were 80.01%, 18.11%, and 1.81%, respectively. The majority of proteins (2,111) contained at least two detected phosphorylation sites. Consistent with findings in other fungi, cytoskeletal proteins were among the most highly phosphorylated proteins, and there were differences in Gene Ontology (GO) terms for proteins with serine and threonine versus tyrosine phosphorylation sites. This large-scale analysis identified phosphosites in protein components of Mediator, an important transcriptional coregulatory protein complex. A targeted analysis of the phosphosites in Mediator complex proteins confirmed the large-scale studies, and further in vitro assays identified a subset of these phosphorylations that were catalyzed by Cdk8 (Ssn3), a kinase within the Mediator complex. These data represent the deepest single analysis of a fungal phosphoproteome and lay the groundwork for future analyses of the C. albicans phosphoproteome and specific phosphoproteins. </p>","PeriodicalId":11891,"journal":{"name":"Eukaryotic Cell","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2015-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1128/EC.00011-15","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"33111323","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Eukaryotic CellPub Date : 2015-05-01Epub Date: 2015-03-06DOI: 10.1128/EC.00262-14
Sabrina J Nolan, Julia D Romano, Thomas Luechtefeld, Isabelle Coppens
{"title":"Neospora caninum Recruits Host Cell Structures to Its Parasitophorous Vacuole and Salvages Lipids from Organelles.","authors":"Sabrina J Nolan, Julia D Romano, Thomas Luechtefeld, Isabelle Coppens","doi":"10.1128/EC.00262-14","DOIUrl":"https://doi.org/10.1128/EC.00262-14","url":null,"abstract":"<p><p>Toxoplasma gondii and Neospora caninum, which cause the diseases toxoplasmosis and neosporosis, respectively, are two closely related apicomplexan parasites. They have similar heteroxenous life cycles and conserved genomes and share many metabolic features. Despite these similarities, T. gondii and N. caninum differ in their transmission strategies and zoonotic potential. Comparative analyses of the two parasites are important to identify the unique biological features that underlie the basis of host preference and pathogenicity. T. gondii and N. caninum are obligate intravacuolar parasites; in contrast to T. gondii, events that occur during N. caninum infection remain largely uncharacterized. We examined the capability of N. caninum (Liverpool isolate) to interact with host organelles and scavenge nutrients in comparison to that of T. gondii (RH strain). N. caninum reorganizes the host microtubular cytoskeleton and attracts endoplasmic reticulum (ER), mitochondria, lysosomes, multivesicular bodies, and Golgi vesicles to its vacuole though with some notable differences from T. gondii. For example, the host ER gathers around the N. caninum parasitophorous vacuole (PV) but does not physically associate with the vacuolar membrane; the host Golgi apparatus surrounds the N. caninum PV but does not fragment into ministacks. N. caninum relies on plasma lipoproteins and scavenges cholesterol from NPC1-containing endocytic organelles. This parasite salvages sphingolipids from host Golgi Rab14 vesicles that it sequesters into its vacuole. Our data highlight a remarkable degree of conservation in the intracellular infection program of N. caninum and T. gondii. The minor differences between the two parasites related to the recruitment and rearrangement of host organelles around their vacuoles likely reflect divergent evolutionary paths. </p>","PeriodicalId":11891,"journal":{"name":"Eukaryotic Cell","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2015-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1128/EC.00262-14","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"33111320","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Eukaryotic CellPub Date : 2015-05-01Epub Date: 2015-03-13DOI: 10.1128/EC.00019-15
Sharon King-Keller, Christina A Moore, Roberto Docampo, Silvia N J Moreno
{"title":"Ca2+ Regulation of Trypanosoma brucei Phosphoinositide Phospholipase C.","authors":"Sharon King-Keller, Christina A Moore, Roberto Docampo, Silvia N J Moreno","doi":"10.1128/EC.00019-15","DOIUrl":"https://doi.org/10.1128/EC.00019-15","url":null,"abstract":"<p><p>We characterized a phosphoinositide phospholipase C (PI-PLC) from the procyclic form (PCF) of Trypanosoma brucei. The protein contains a domain organization characteristic of typical PI-PLCs, such as X and Y catalytic domains, an EF-hand calcium-binding motif, and a C2 domain, but it lacks a pleckstrin homology (PH) domain. In addition, the T. brucei PI-PLC (TbPI-PLC) contains an N-terminal myristoylation consensus sequence found only in trypanosomatid PI-PLCs. A peptide containing this N-terminal domain fused to green fluorescent protein (GFP) was targeted to the plasma membrane. TbPI-PLC enzymatic activity was stimulated by Ca(2+) concentrations below the cytosolic levels in the parasite, suggesting that the enzyme is constitutively active. TbPI-PLC hydrolyzes both phosphatidylinositol (PI) and phosphatidylinositol 4,5-bisphosphate (PIP2), with a higher affinity for PIP2. We found that modification of a single amino acid in the EF-hand motif greatly affected the protein's Ca(2+) sensitivity and substrate preference, demonstrating the role of this motif in Ca(2+) regulation of TbPI-PLC. Endogenous TbPI-PLC localizes to intracellular vesicles and might be using an intracellular source of PIP2. Knockdown of TbPI-PLC expression by RNA interference (RNAi) did not result in growth inhibition, although enzymatic activity was still present in parasites, resulting in hydrolysis of PIP2 and a contribution to the inositol 1,4,5-trisphosphate (IP3)/diacylglycerol (DAG) pathway. </p>","PeriodicalId":11891,"journal":{"name":"Eukaryotic Cell","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2015-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1128/EC.00019-15","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"33127879","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Eukaryotic CellPub Date : 2015-05-01Epub Date: 2015-03-27DOI: 10.1128/EC.00277-14
Rafael Jaimes-Arroyo, Fernando Lara-Rojas, Özgür Bayram, Oliver Valerius, Gerhard H Braus, Jesús Aguirre
{"title":"The SrkA Kinase Is Part of the SakA Mitogen-Activated Protein Kinase Interactome and Regulates Stress Responses and Development in Aspergillus nidulans.","authors":"Rafael Jaimes-Arroyo, Fernando Lara-Rojas, Özgür Bayram, Oliver Valerius, Gerhard H Braus, Jesús Aguirre","doi":"10.1128/EC.00277-14","DOIUrl":"https://doi.org/10.1128/EC.00277-14","url":null,"abstract":"<p><p>Fungi and many other eukaryotes use specialized mitogen-activated protein kinases (MAPK) of the Hog1/p38 family to transduce environmental stress signals. In Aspergillus nidulans, the MAPK SakA and the transcription factor AtfA are components of a central multiple stress-signaling pathway that also regulates development. Here we characterize SrkA, a putative MAPK-activated protein kinase, as a novel component of this pathway. ΔsrkA and ΔsakA mutants share a derepressed sexual development phenotype. However, ΔsrkA mutants are not sensitive to oxidative stress, and in fact, srkA inactivation partially suppresses the sensitivity of ΔsakA mutant conidia to H2O2, tert-butyl-hydroperoxide (t-BOOH), and menadione. In the absence of stress, SrkA shows physical interaction with nonphosphorylated SakA in the cytosol. We show that H2O2 induces a drastic change in mitochondrial morphology consistent with a fission process and the relocalization of SrkA to nuclei and mitochondria, depending on the presence of SakA. SakA-SrkA nuclear interaction is also observed during normal asexual development in dormant spores. Using SakA and SrkA S-tag pulldown and purification studies coupled to mass spectrometry, we found that SakA interacts with SrkA, the stress MAPK MpkC, the PPT1-type phosphatase AN6892, and other proteins involved in cell cycle regulation, DNA damage response, mRNA stability and protein synthesis, mitochondrial function, and other stress-related responses. We propose that oxidative stress induces DNA damage and mitochondrial fission and that SakA and SrkA mediate cell cycle arrest and regulate mitochondrial function during stress. Our results provide new insights into the mechanisms by which SakA and SrkA regulate the remodelling of cell physiology during oxidative stress and development. </p>","PeriodicalId":11891,"journal":{"name":"Eukaryotic Cell","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2015-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1128/EC.00277-14","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"33170247","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}