scholarly journals A Heat Shock Protein 48 (HSP48) Biomolecular Condensate Is Induced duringDictyostelium discoideumDevelopment

mSphere ◽  
2019 ◽  
Vol 4 (3) ◽  
Author(s):  
Stephanie Santarriaga ◽  
Alicia Fikejs ◽  
Jamie Scaglione ◽  
K. Matthew Scaglione
Keyword(s):  
Heat Shock ◽  
Heat Shock Protein ◽  
Dictyostelium Discoideum ◽  
Fruiting Body ◽  
Developmental Process ◽  
Cellular Stress ◽  
Content Type ◽  
Social Amoeba ◽  
Content Development ◽  
The Social

ABSTRACTThe social amoebaDictyostelium discoideum’s proteome contains a vast array of simple sequence repeats, providing a unique model to investigate proteostasis. Upon conditions of cellular stress,D. discoideumundergoes a developmental process, transitioning from a unicellular amoeba to a multicellular fruiting body. Little is known about how proteostasis is maintained duringD. discoideum’s developmental process. Here, we have identified a novel α-crystallin domain-containing protein, heat shock protein 48 (HSP48), that is upregulated duringD. discoideumdevelopment. HSP48 functions in part by forming a biomolecular condensate via its highly positively charged intrinsically disordered carboxy terminus. In addition to HSP48, the highly negatively charged primordial chaperone polyphosphate is also upregulated duringD. discoideumdevelopment, and polyphosphate functions to stabilize HSP48. Upon germination, levels of both HSP48 and polyphosphate dramatically decrease, consistent with a role for HSP48 and polyphosphate during development. Together, our data demonstrate that HSP48 is strongly induced duringDictyostelium discoideumdevelopment. We also demonstrate that HSP48 forms a biomolecular condensate and that polyphosphate is necessary to stabilize the HSP48 biomolecular condensate.IMPORTANCEDuring cellular stress, many microbes undergo a transition to a dormant state. This includes the social amoebaDictyostelium discoideumthat transitions from a unicellular amoeba to a multicellular fruiting body upon starvation. In this work, we identify heat shock protein 48 (HSP48) as a chaperone that is induced during development. We also show that HSP48 forms a biomolecular condensate and is stabilized by polyphosphate. The findings here identifyDictyostelium discoideumas a novel microbe to investigate protein quality control pathways during the transition to dormancy.

scholarly journals Cooperation and conflict in the social amoeba Dictyostelium discoideum

2019 ◽  
Vol 63 (8-9-10) ◽  
pp. 371-382
Author(s):  
James M. Medina ◽  
P.M. Shreenidhi ◽  
Tyler J. Larsen ◽  
David C. Queller ◽  
Joan E. Strassmann
Keyword(s):  
Dictyostelium Discoideum ◽  
Fruiting Body ◽  
Sexual Cycle ◽  
Evolution Of Cooperation ◽  
Bacterial Symbionts ◽  
Spore Dispersal ◽  
Social Amoeba ◽  
The Social ◽  
The Relationship ◽  
Insight Into

The social amoeba Dictyostelium discoideum has provided considerable insight into the evolution of cooperation and conflict. Under starvation, D. discoideum amoebas cooperate to form a fruiting body comprised of hardy spores atop a stalk. The stalk development is altruistic because stalk cells die to aid spore dispersal. The high relatedness of cells in fruiting bodies in nature implies that this altruism often benefits relatives. However, since the fruiting body forms through aggregation there is potential for non-relatives to join the aggregate and create conflict over spore and stalk fates. Cheating is common in chimeras of social amoebas, where one genotype often takes advantage of the other and makes more spores. This social conflict is a significant force in nature as indicated by rapid rates of adaptive evolution in genes involved in cheating and its resistance. However, cheating can be prevented by high relatedness, allorecognition via tgr genes, pleiotropy and evolved resistance. Future avenues for the study of cooperation and conflict in D. discoideum include the sexual cycle as well as the relationship between D. discoideum and its bacterial symbionts. D. discoideum’s tractability in the laboratory as well as its uncommon mode of aggregative multicellularity have established it as a promising model for future studies of cooperation and conflict.

scholarly journals A Novel Glycolipid Biosurfactant Confers Grazing Resistance upon Pantoea ananatis BRT175 against the Social Amoeba Dictyostelium discoideum

mSphere ◽  
2016 ◽  
Vol 1 (1) ◽  
Author(s):  
Derek D. N. Smith ◽  
Arvin Nickzad ◽  
Eric Déziel ◽  
John Stavrinides
Keyword(s):  
Dictyostelium Discoideum ◽  
Opportunistic Infections ◽  
Pantoea Ananatis ◽  
Content Type ◽  
Social Amoeba ◽  
Host Interaction ◽  
Glycolipid Biosurfactant ◽  
The Social ◽  
Grazing Resistance ◽  
Opportunistic Human Pathogen

ABSTRACT The genetic factors used for host interaction by the opportunistic human pathogen Pantoea ananatis are largely unknown. We identified two genes that are important for the production of a biosurfactant that confers grazing resistance against the social amoeba Dictyostelium discoideum. We show that the biosurfactant, which exhibits cytotoxicity toward the amoebae, is a glycolipid that incorporates a hexose rather than rhamnose. The production of this biosurfactant may confer a competitive advantage in the environment and could potentially contribute to the establishment of opportunistic infections. Pantoea is a versatile genus of bacteria with both plant- and animal-pathogenic strains, some of which have been suggested to cause human infections. There is, however, limited knowledge on the potential determinants used for host association and pathogenesis in animal systems. In this study, we used the model host Dictyostelium discoideum to show that isolates of Pantoea ananatis exhibit differential grazing susceptibility, with some being resistant to grazing by the amoebae. We carried out a high-throughput genetic screen of one grazing-resistant isolate, P. ananatis BRT175, using the D. discoideum pathosystem to identify genes responsible for the resistance phenotype. Among the 26 candidate genes involved in grazing resistance, we identified rhlA and rhlB, which we show are involved in the biosynthesis of a biosurfactant that enables swarming motility in P. ananatis BRT175. Using liquid chromatography-mass spectrometry (LC-MS), the biosurfactant was shown to be a glycolipid with monohexose-C10-C10 as the primary congener. We show that this novel glycolipid biosurfactant is cytotoxic to the amoebae and is capable of compromising cellular integrity, leading to cell lysis. The production of this biosurfactant may be important for bacterial survival in the environment and could contribute to the establishment of opportunistic infections. IMPORTANCE The genetic factors used for host interaction by the opportunistic human pathogen Pantoea ananatis are largely unknown. We identified two genes that are important for the production of a biosurfactant that confers grazing resistance against the social amoeba Dictyostelium discoideum. We show that the biosurfactant, which exhibits cytotoxicity toward the amoebae, is a glycolipid that incorporates a hexose rather than rhamnose. The production of this biosurfactant may confer a competitive advantage in the environment and could potentially contribute to the establishment of opportunistic infections.

scholarly journals A Surface Glycoprotein Indispensable for Gamete Fusion in the Social Amoeba Dictyostelium discoideum

2012 ◽  
Vol 11 (5) ◽  
pp. 638-644 ◽  
Author(s):  
Yoshinori Araki ◽  
Hideki D. Shimizu ◽  
Kentaro Saeki ◽  
Marina Okamoto ◽  
Lixy Yamada ◽  
...  
Keyword(s):  
Cell Adhesion ◽  
Sexual Reproduction ◽  
Dictyostelium Discoideum ◽  
Mating Type ◽  
Surface Glycoprotein ◽  
Sexual Cycle ◽  
Dependent Manner ◽  
Content Type ◽  
Social Amoeba ◽  
The Social

ABSTRACT Sexual reproduction is essential for the maintenance of species in a wide variety of multicellular organisms, and even unicellular organisms that normally proliferate asexually possess a sexual cycle because of its contribution to increased genetic diversity. Information concerning the molecules involved in fertilization is accumulating for many species of the metazoan, plant, and fungal lineages, and the evolutionary consideration of sexual reproduction systems is now an interesting issue. Macrocyst formation in the social amoeba Dictyostelium discoideum is a sexual process in which cells become sexually mature under dark and submerged conditions and fuse with complementary mating-type cells. In the present study, we isolated D. discoideum insertional mutants defective in sexual cell fusion and identified the relevant gene, macA , which encodes a highly glycosylated, 2,041-amino-acid membrane protein (MacA). Although its overall similarity is restricted to proteins of unknown function within dictyostelids, it contains LamGL and discoidin domains, which are implicated in cell adhesion. The growth and development of macA -null mutants were indistinguishable from those of the parental strain. The overexpression of macA using the V18 promoter in a macA -null mutant completely restored its sexual defects. Although the macA gene encoded exactly the same protein in a complementary mating-type strain, it was expressed at a much lower level. These results suggest that MacA is indispensable for gamete interactions in D. discoideum , probably via cell adhesion. There is a possibility that it is controlled in a mating-type-dependent manner.

scholarly journals Amino Acid Repeats Cause Extraordinary Coding Sequence Variation in the Social Amoeba Dictyostelium discoideum

PLoS ONE ◽  
2012 ◽  
Vol 7 (9) ◽  
pp. e46150 ◽  
Author(s):  
Clea Scala ◽  
Xiangjun Tian ◽  
Natasha J. Mehdiabadi ◽  
Margaret H. Smith ◽  
Gerda Saxer ◽  
...  
Keyword(s):  
Amino Acid ◽  
Dictyostelium Discoideum ◽  
Sequence Variation ◽  
Social Amoeba ◽  
Coding Sequence ◽  
Amino Acid Repeats ◽  
The Social

scholarly journals Peripheral T-Cell Reactivity to Heat Shock Protein 70 and Its Cofactor GrpE from Tropheryma whipplei Is Reduced in Patients with Classical Whipple's Disease

2017 ◽  
Vol 85 (8) ◽  
Author(s):  
Lucia Trotta ◽  
Kathleen Weigt ◽  
Katina Schinnerling ◽  
Anika Geelhaar-Karsch ◽  
Gerrit Oelkers ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Heat Shock ◽  
Heat Shock Protein ◽  
Heat Shock Protein 70 ◽  
T Cell Responses ◽  
Tropheryma Whipplei ◽  
Content Type ◽  
Cell Responses ◽  
Ifn Γ

ABSTRACT Classical Whipple's disease (CWD) is characterized by the lack of specific Th1 response toward Tropheryma whipplei in genetically predisposed individuals. The cofactor GrpE of heat shock protein 70 (Hsp70) from T. whipplei was previously identified as a B-cell antigen. We tested the capacity of Hsp70 and GrpE to elicit specific proinflammatory T-cell responses. Peripheral mononuclear cells from CWD patients and healthy donors were stimulated with T. whipplei lysate or recombinant GrpE or Hsp70 before levels of CD40L, CD69, perforin, granzyme B, CD107a, and gamma interferon (IFN-γ) were determined in T cells by flow cytometry. Upon stimulation with total bacterial lysate or recombinant GrpE or Hsp70 of T. whipplei, the proportions of activated effector CD4+ T cells, determined as CD40L+ IFN-γ+, were significantly lower in patients with CWD than in healthy controls; CD8+ T cells of untreated CWD patients revealed an enhanced activation toward unspecific stimulation and T. whipplei-specific degranulation, although CD69+ IFN-γ+ CD8+ T cells were reduced upon stimulation with T. whipplei lysate and recombinant T. whipplei-derived proteins. Hsp70 and its cofactor GrpE are immunogenic in healthy individuals, eliciting effective responses against T. whipplei to control bacterial spreading. The lack of specific T-cell responses against these T. whipplei-derived proteins may contribute to the pathogenesis of CWD.

scholarly journals Activation of protein kinase B (Akt/RAC-protein kinase) by cellular stress and its association with heat shock protein Hsp27

FEBS Letters ◽  
1997 ◽  
Vol 410 (2-3) ◽  
pp. 493-498 ◽  
Author(s):  
Hiroaki Konishi ◽  
Hidenori Matsuzaki ◽  
Motonari Tanaka ◽  
Yukitoshi Takemura ◽  
Shun'ichi Kuroda ◽  
...  
Keyword(s):  
Heat Shock ◽  
Protein Kinase ◽  
Heat Shock Protein ◽  
Protein Kinase B ◽  
Cellular Stress

scholarly journals Ribosome Profiling Reveals HSP90 Inhibitor Effects on Stage-Specific Protein Synthesis in Leishmania donovani

mSystems ◽  
2018 ◽  
Vol 3 (6) ◽  
Author(s):  
Eugenia Bifeld ◽  
Stephan Lorenzen ◽  
Katharina Bartsch ◽  
Juan-José Vasquez ◽  
T. Nicolai Siegel ◽  
...  
Keyword(s):  
Gene Expression ◽  
Protein Synthesis ◽  
Heat Shock ◽  
Heat Shock Protein ◽  
Leishmania Donovani ◽  
Specific Protein ◽  
Ribosome Profiling ◽  
Severe Illness ◽  
Content Type ◽  
Hsp90 Activity

ABSTRACT The 90-kDa heat shock protein (HSP90) of eukaryotes is a highly abundant and essential chaperone required for the maturation of regulatory and signal proteins. In the protozoan parasite Leishmania donovani, causative agent of the fatal visceral leishmaniasis, HSP90 activity is essential for cell proliferation and survival. Even more importantly, its inhibition causes life cycle progression from the insect stage to the pathogenic, mammalian stage. To unravel the molecular impact of HSP90 activity on the parasites’ gene expression, we performed a ribosome profiling analysis of L. donovani, comparing genome-wide protein synthesis patterns in the presence and absence of the HSP90-specific inhibitor radicicol and an ectopically expressed radicicol-resistant HSP90 variant. We find that ribosome-protected RNA faithfully maps open reading frames and represents 97% of the annotated protein-coding genes of L. donovani. Protein synthesis was found to correlate poorly with RNA steady-state levels, indicating a regulated translation as primary mechanism for HSP90-dependent gene expression. The results confirm inhibitory effects of HSP90 on the synthesis of Leishmania proteins that are associated with the pathogenic, intracellular stage of the parasite. Those include heat shock proteins, redox enzymes, virulence-enhancing surface proteins, proteolytic pathways, and a complete set of histones. Conversely, HSP90 promotes fatty acid synthesis enzymes. Complementing radicicol treatment with the radicicol-resistant HSP90rr variant revealed important off-target radicicol effects that control a large number of the above-listed proteins. Leishmania lacks gene-specific transcription regulation and relies on regulated translation instead. Our ribosome footprinting analysis demonstrates a controlling function of HSP90 in stage-specific protein synthesis but also significant, HSP90-independent effects of the inhibitor radicicol. IMPORTANCE Leishmania parasites cause severe illness in humans and animals. They exist in two developmental stages, insect form and mammalian form, which differ in shape and gene expression. By mapping and quantifying RNA fragments protected by protein synthesis complexes, we determined the rates of protein synthesis for >90% of all Leishmania proteins in response to the inhibition of a key regulatory protein, the 90-kDa heat shock protein. We find that Leishmania depends on a regulation of protein synthesis for controlling its gene expression and that heat shock protein 90 inhibition can trigger the developmental program from insect form to mammalian form of the pathogen.

Sign in / Sign up

Export Citation Format

Share Document