scholarly journals Membrane-Associated Proteins in Giardia lamblia

Genes ◽  
2018 ◽  
Vol 9 (8) ◽  
pp. 404 ◽  
Author(s):  
María Touz ◽  
Constanza Feliziani ◽  
Andrea Rópolo
Keyword(s):  
Giardia Lamblia ◽  
Genome Database ◽  
Associated Proteins ◽  
And Function

The manner in which membrane-associated proteins interact with the membrane defines their subcellular fate and function. This interaction relies on the characteristics of the proteins, their journey after synthesis, and their interaction with other proteins or enzymes. Understanding these properties may help to define the function of a protein and also the role of an organelle. In the case of microorganisms like protozoa parasites, it may help to understand singular features that will eventually lead to the design of parasite-specific drugs. The protozoa parasite Giardia lamblia is an example of a widespread parasite that has been infecting humans and animals from ancestral times, adjusting itself to the changes of the environment inside and outside the host. Several membrane-associated proteins have been posted in the genome database GiardiaDB, although only a few of them have been characterized. This review discusses the data regarding membrane-associated proteins in relationship with lipids and specific organelles and their implication in the discovery of anti-giardial therapies.

scholarly journals Disc and Actin-Associated Protein 1 Influence Host Attachment in the Intestinal Parasite Giardia lamblia

2021 ◽  
Author(s):  
Melissa C. Steele-Ogus ◽  
Ava M. Obenaus ◽  
Nathan J. Sniadecki ◽  
Alexander R. Paredez
Keyword(s):  
Conformational Changes ◽  
Giardia Lamblia ◽  
Actin Polymerization ◽  
Intestinal Parasite ◽  
Interacting Proteins ◽  
Associated Proteins ◽  
Promising Area ◽  
Ventral Disc ◽  
And Function

The deep-branching eukaryote Giardia lamblia is an extracellular parasite that attaches to the host intestine via a microtubule-based structure called the ventral disc. Control of attachment is mediated in part by the movement of two regions of the ventral disc that either permit or exclude the passage of fluid under the disc. Several known disc-associated proteins (DAPs) contribute to disc structure and function, but no force-generating protein has been identified among them. We recently identified several Giardia actin (GlActin) interacting proteins at the ventral disc, which could potentially employ actin polymerization for force generation and disc conformational changes. One of these proteins, Disc and Actin Associated Protein 1 (DAAP1), is highly enriched at the two regions of the disc previously shown to be important for fluid flow during attachment. In this study, we investigate the role of both GlActin and DAAP1 in ventral disc morphology and function. We confirmed interaction between GlActin and DAAP1 through coimmunoprecipitation, and used immunofluorescence to localize both proteins throughout the cell cycle and during trophozoite attachment. Similar to other DAPs, the association of DAAP1 with the disc is stable, except during cell division when the disc disassembles. Depletion of GlActin by translation-blocking antisense morpholinos resulted in both impaired attachment and defects in the ventral disc, indicating that GlActin contributes to disc-mediated attachment. Depletion of DAAP1 through CRISPR interference resulted in intact discs but impaired attachment, gating, and flow under the disc. As attachment is essential for infection, elucidation of these and other molecular mediators is a promising area for development of new therapeutics against a ubiquitous parasite.

scholarly journals Membrane-associated phase separation: organization and function emerge from a two-dimensional milieu

2021 ◽  
Author(s):  
Jonathon A Ditlev
Keyword(s):  
Phase Separation ◽  
Cell Biology ◽  
Cellular Environment ◽  
Condensate Formation ◽  
Associated Proteins ◽  
Available Technology ◽  
And Function ◽  
Surrounding Membrane

Abstract Liquid‒liquid phase separation (LLPS) of biomolecules has emerged as an important mechanism that contributes to cellular organization. Phase separated biomolecular condensates, or membrane-less organelles, are compartments composed of specific biomolecules without a surrounding membrane in the nucleus and cytoplasm. LLPS also occurs at membranes, where both lipids and membrane-associated proteins can de-mix to form phase separated compartments. Investigation of these membrane-associated condensates using in vitro biochemical reconstitution and cell biology has provided key insights into the role of phase separation in membrane domain formation and function. However, these studies have generally been limited by available technology to study LLPS on model membranes and the complex cellular environment that regulates condensate formation, composition, and function. Here, I briefly review our current understanding of membrane-associated condensates, establish why LLPS can be advantageous for certain membrane-associated condensates, and offer a perspective for how these condensates may be studied in the future.

scholarly journals Chromatin Enrichment for Proteomics in Plants (ChEP-P) Implicates the Histone Reader ALFIN-LIKE 6 in Jasmonate Signalling

2021 ◽  
Author(s):  
Isabel Cristina Vélez-Bermúdez ◽  
Wolfgang Schmidt
Keyword(s):  
Histone Variants ◽  
Homeodomain Protein ◽  
Chromatin Dynamics ◽  
Histone 3 ◽  
Plant Homeodomain ◽  
Associated Proteins ◽  
Bona Fide ◽  
Covalent Modifications ◽  
And Function

Abstract BackgroundCovalent modifications of core histonesgoverndownstream DNA-templated processes such as transcription by altering chromatin structure and function. Previously, we reported that the plant homeodomain protein ALFIN-LIKE6 (AL6), a bona fide histone reader that preferentially binds trimethylated lysin 4 on histone 3 (H3K4me3), is critical for recalibration of cellular phosphate (Pi) homeostasis and root hair elongation under Pi-deficient conditions. ResultsHere, we demonstrate that AL6 is also involved in the response of Arabidopsis seedlings to jasmonic acid (JA) during skotomorphogenesis, possibly by modulating chromatin dynamics that affect the transcriptional regulation of JA-responsivegenes. Dark-grown al6 seedlings showed a compromised reduction in hypocotyl elongation upon exogenously supplied JA, a response that was calibrated by the availability of Pi in the growth medium. A comparison of protein profiles between wild-type and al6 mutant seedlings using a quantitative Chromatin Enrichment for Proteomics (ChEP) approach,that we modified for plant tissue and designated ChEP-P (ChEP in Plants), yielded a comprehensive suite of chromatin-associated proteins and candidates that may be causative for the mutant phenotype. ConclusionsAltered abundance of proteins involved in chromatin organization in al6 seedlings suggests a role of AL6 in coordinating the deposition of histone variants upon perception of internal or environmental stimuli. Our study shows that ChEP-P is well suited to gain holistic insights into chromatin-related processes in plants. Data are available via ProteomeXchange with identifier PXD026541.

scholarly journals How Does SUMO Participate in Spindle Organization?

Cells ◽  
2019 ◽  
Vol 8 (8) ◽  
pp. 801
Author(s):  
Abrieu ◽  
Liakopoulos
Keyword(s):  
Dna Repair ◽  
Protein Assemblies ◽  
Cellular Mechanisms ◽  
Future Directions ◽  
Kinetochore Assembly ◽  
Associated Proteins ◽  
Long Time ◽  
And Function ◽  
Dependent Processes

The ubiquitin-like protein SUMO is a regulator involved in most cellular mechanisms. Recent studies have discovered new modes of function for this protein. Of particular interest is the ability of SUMO to organize proteins in larger assemblies, as well as the role of SUMO-dependent ubiquitylation in their disassembly. These mechanisms have been largely described in the context of DNA repair, transcriptional regulation, or signaling, while much less is known on how SUMO facilitates organization of microtubule-dependent processes during mitosis. Remarkably however, SUMO has been known for a long time to modify kinetochore proteins, while more recently, extensive proteomic screens have identified a large number of microtubule- and spindle-associated proteins that are SUMOylated. The aim of this review is to focus on the possible role of SUMOylation in organization of the spindle and kinetochore complexes. We summarize mitotic and microtubule/spindle-associated proteins that have been identified as SUMO conjugates and present examples regarding their regulation by SUMO. Moreover, we discuss the possible contribution of SUMOylation in organization of larger protein assemblies on the spindle, as well as the role of SUMO-targeted ubiquitylation in control of kinetochore assembly and function. Finally, we propose future directions regarding the study of SUMOylation in regulation of spindle organization and examine the potential of SUMO and SUMO-mediated degradation as target for antimitotic-based therapies.

scholarly journals Complexome profiling on the Chlamydomonas lpa2 mutant reveals insights into PSII biogenesis and new PSII associated proteins

2021 ◽  
Author(s):  
Benjamin Spaniol ◽  
Julia Lang ◽  
Benedikt Venn ◽  
Lara Schake ◽  
Frederik Sommer ◽  
...  
Keyword(s):  
Thylakoid Membrane ◽  
Complex Dynamics ◽  
Cytochrome B6f Complex ◽  
Wild Type ◽  
Low Light ◽  
Chlorophyll Breakdown ◽  
Associated Proteins ◽  
And Function ◽  
B6f Complex

Abstract While the composition and function of the major thylakoid membrane complexes are well understood, comparatively little is known about their biogenesis. The goal of this work was to shed more light on the role of auxiliary factors in the biogenesis of photosystem II (PSII). Here we have identified the homolog of LOW PSII ACCUMULATION 2 (LPA2) in Chlamydomonas. A Chlamydomonas reinhardtii lpa2 mutant grew slower in low light, was hypersensitive to high light, and exhibited aberrant structures in thylakoid membrane stacks. Chlorophyll fluorescence (Fv/Fm) was reduced by 38%. Synthesis and stability of newly made PSII core subunits D1, D2, CP43, and CP47 were not impaired. However, complexome profiling revealed that in the mutant CP43 was reduced to ~23% and D1, D2, and CP47 to ~30% of wild type levels. Levels of PSI and the cytochrome b6f complex were unchanged, while levels of the ATP synthase were increased by ~29%. PSII supercomplexes, dimers, and monomers were reduced to ~7%, ~26%, and ~60% of wild type levels, while RC47 was increased ~6-fold and LHCII by ~27%. We propose that LPA2 catalyses a step during PSII assembly without which PSII monomers and further assemblies become unstable and prone to degradation. The LHCI antenna was more disconnected from PSI in the lpa2 mutant, presumably as an adaptive response to reduce excitation of PSI. From the co-migration profiles of 1734 membrane-associated proteins, we identified three novel putative PSII associated proteins with potential roles in regulating PSII complex dynamics, assembly, and chlorophyll breakdown.

scholarly journals Map1b Is Required for Axon Guidance and Is Involved in the Development of the Central and Peripheral Nervous System

2000 ◽  
Vol 151 (6) ◽  
pp. 1169-1178 ◽  
Author(s):  
Arabella Meixner ◽  
Silke Haverkamp ◽  
Heinz Wässle ◽  
Susanne Führer ◽  
Johann Thalhammer ◽  
...  
Keyword(s):  
Nervous System ◽  
Nerve Conduction Velocity ◽  
Developmental Defect ◽  
Myelinated Fiber ◽  
Microtubule Associated Proteins ◽  
Associated Proteins ◽  
And Function ◽  
The Brain ◽  
Deficient Mice

Microtubule-associated proteins such as MAP1B have long been suspected to play an important role in neuronal differentiation, but proof has been lacking. Previous MAP1B gene targeting studies yielded contradictory and inconclusive results and did not reveal MAP1B function. In contrast to two earlier efforts, we now describe generation of a complete MAP1B null allele. Mice heterozygous for this MAP1B deletion were not affected. Homozygous mutants were viable but displayed a striking developmental defect in the brain, the selective absence of the corpus callosum, and the concomitant formation of myelinated fiber bundles consisting of misguided cortical axons. In addition, peripheral nerves of MAP1B-deficient mice had a reduced number of large myelinated axons. The myelin sheaths of the remaining axons were of reduced thickness, resulting in a decrease of nerve conduction velocity in the adult sciatic nerve. On the other hand, the anticipated involvement of MAP1B in retinal development and γ-aminobutyric acid C receptor clustering was not substantiated. Our results demonstrate an essential role of MAP1B in development and function of the nervous system and resolve a previous controversy over its importance.

scholarly journals Role of Nucleotide Binding in Septin-Septin Interactions and Septin Localization in Saccharomyces cerevisiae

2008 ◽  
Vol 28 (16) ◽  
pp. 5120-5137 ◽  
Author(s):  
Satish Nagaraj ◽  
Ashok Rajendran ◽  
Charles E. Jackson ◽  
Mark S. Longtine
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Nucleotide Binding ◽  
Temperature Sensitive ◽  
Associated Proteins ◽  
And Function ◽  
Bud Site ◽  
Two Hybrid

ABSTRACT Septins are a conserved family of eukaryotic GTP-binding, filament-forming proteins. In Saccharomyces cerevisiae, five septins (Cdc3p, Cdc10p, Cdc11p, Cdc12p, and Shs1p) form a complex and colocalize to the incipient bud site and as a collar of filaments at the neck of budded cells. Septins serve as a scaffold to localize septin-associated proteins involved in diverse processes and as a barrier to diffusion of membrane-associated proteins. Little is known about the role of nucleotide binding in septin function. Here, we show that Cdc3p, Cdc10p, Cdc11p, and Cdc12p all bind GTP and that P-loop and G4 motif mutations affect nucleotide binding and result in temperature-sensitive defects in septin localization and function. Two-hybrid, in vitro, and in vivo analyses show that for all four septins nucleotide binding is important in septin-septin interactions and complex formation. In the absence of complete complexes, septins do not localize to the cortex, suggesting septin localization factors interact only with complete complexes. When both complete and partial complexes are present, septins localize to the cortex but do not form a collar, perhaps because of an inability to form filaments. We find no evidence that nucleotide binding is specifically involved in the interaction of septins with septin-associated proteins.

scholarly journals Genome-wide identification and characterization of Dof transcription factors in eggplant (Solanum melongena L.)

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e4481 ◽  
Author(s):  
Qingzhen Wei ◽  
Wuhong Wang ◽  
Tianhua Hu ◽  
Haijiao Hu ◽  
Weihai Mao ◽  
...  
Keyword(s):  
Transcription Factors ◽  
Expression Patterns ◽  
Solanum Melongena ◽  
Genome Database ◽  
Homologous Genes ◽  
Genome Wide ◽  
The Family ◽  
And Function

Eggplant (Solanum melongena L.) is an important vegetable cultivated in Asia, Africa and southern Europe and, following tomato and pepper, ranks as the third most important solanaceous vegetable crop. The Dof (DNA-binding with one finger) family is a group of plant-specific transcription factors that play important roles in plant growth, development, and response to biotic and abiotic stresses. The genes in the Dof family have been identified and analysed in many plant species, but the information remains lacking for eggplant. In the present study, we identified 29 SmeDof members from the eggplant genome database, which were classifed into nine subgroups. The phylogeny, gene structure, conserved motifs and homologous genes of SmeDof genes were comprehensively investigated. Subsequently, we analysed the expression patterns of SmeDof genes in six different eggplant subspecies. The results provide novel insights into the family of SmeDof genes and will promote the understanding of the structure and function of Dof genes in eggplant, and the role of Dof expression during stress.

scholarly journals Chromatin enrichment for Proteomics in Plants (ChEP-P) implicates the histone reader ALFIN-LIKE 6 in jasmonate signalling

2021 ◽  
Author(s):  
Isabel Cristina Velez-Bermudez ◽  
Wolfgang Schmidt
Keyword(s):  
Histone Variants ◽  
Homeodomain Protein ◽  
Chromatin Dynamics ◽  
Histone 3 ◽  
Core Histones ◽  
Associated Proteins ◽  
Bona Fide ◽  
Covalent Modifications ◽  
And Function

Covalent modifications of core histones govern downstream DNA-templated processes such as transcription by altering chromatin structure and function. Previously, we reported that the plant homeodomain protein ALFIN-LIKE 6 (AL6), a bona fide histone reader that preferentially binds trimethylated lysin 4 on histone 3 (H3K4me3), is critical for recalibration of cellular phosphate (Pi) homeostasis and root hair elongation under Pi-deficient conditions. Here, we demonstrate that AL6 is also involved in the response of Arabidopsis seedlings to jasmonic acid (JA) during skotomorphogenesis, possibly by modulating chromatin dynamics that affect the transcriptional regulation of JA-responsive genes. Dark-grown al6 seedlings showed a compromised reduction in hypocotyl elongation upon exogenously supplied JA, a response that was calibrated by the availability of Pi in the growth medium. A comparison of protein profiles between wild-type and al6 mutant seedlings using a quantitative Chromatin Enrichment for Proteomics (ChEP) approach, that we modified for plant tissue and designated ChEP-P (ChEP in Plants), yielded a comprehensive suite of chromatin-associated proteins and candidates that may be causative for the mutant phenotype. Altered abundance of proteins involved in chromatin organization in al6 seedlings suggests a role of AL6 in coordinating the deposition of histone variants upon perception of internal or environmental stimuli.

scholarly journals Chromatin enrichment for proteomics in plants (ChEP-P) implicates the histone reader ALFIN-LIKE 6 in jasmonate signalling

BMC Genomics ◽  
2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Isabel Cristina Vélez-Bermúdez ◽  
Wolfgang Schmidt
Keyword(s):  
Histone Variants ◽  
Homeodomain Protein ◽  
Chromatin Dynamics ◽  
Histone 3 ◽  
Core Histones ◽  
Associated Proteins ◽  
Bona Fide ◽  
Covalent Modifications ◽  
And Function

Abstract Background Covalent modifications of core histones govern downstream DNA-templated processes such as transcription by altering chromatin structure and function. Previously, we reported that the plant homeodomain protein ALFIN-LIKE 6 (AL6), a bona fide histone reader that preferentially binds trimethylated lysin 4 on histone 3 (H3K4me3), is critical for recalibration of cellular phosphate (Pi) homeostasis and root hair elongation under Pi-deficient conditions. Results Here, we demonstrate that AL6 is also involved in the response of Arabidopsis seedlings to jasmonic acid (JA) during skotomorphogenesis, possibly by modulating chromatin dynamics that affect the transcriptional regulation of JA-responsive genes. Dark-grown al6 seedlings showed a compromised reduction in hypocotyl elongation upon exogenously supplied JA, a response that was calibrated by the availability of Pi in the growth medium. A comparison of protein profiles between wild-type and al6 mutant seedlings using a quantitative Chromatin Enrichment for Proteomics (ChEP) approach, that we modified for plant tissue and designated ChEP-P (ChEP in Plants), yielded a comprehensive suite of chromatin-associated proteins and candidates that may be causative for the mutant phenotype. Conclusions Altered abundance of proteins involved in chromatin organization in al6 seedlings suggests a role of AL6 in coordinating the deposition of histone variants upon perception of internal or environmental stimuli. Our study shows that ChEP-P is well suited to gain holistic insights into chromatin-related processes in plants. Data are available via ProteomeXchange with identifier PXD026541.

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