The low complexity regions in the C-terminus are essential for the subcellular localisation of Leishmania casein kinase 1 but not for its activity

AbstractCasein Kinase 1 (CK1) family members are serine/threonine protein kinases ubiquitously expressed in eukaryotic organisms. They are involved in a wide range of important cellular processes, such as membrane trafficking, or vesicular transport in organisms from yeast to humans. Due to its broad spectrum of action, CK1 activity and expression is tightly regulated by a number of mechanisms, including subcellular sequestration. Defects in CK1 regulation, localisation or the introduction of mutations in the CK1 coding sequence are often associated with important diseases such as cancer. Increasing evidence suggest that the manipulation of host cell CK1 signalling pathways by intracellular pathogens, either by exploiting the host CK1 or by exporting the CK1 of the pathogen into the host cell may play an important role in infectious diseases. Leishmania CK1.2 is essential for parasite survival and released into the host cell, playing an important role in host pathogen interactions. Although Leishmania CK1.2 has dual role in the parasite and in the host cell, nothing is known about its parasitic localisation and organelle-specific functions. In this study, we show that CK1.2 is a ubiquitous kinase, which is present in the cytoplasm, associated to the cytoskeleton and localised to various organelles, indicating potential roles in kinetoplast and nuclear segregation, as well as ribosomal processing and motility. Furthermore, using truncated mutants, we show for the first time that the two low complexity regions (LCR) present in the C-terminus of CK1.2 are essential for the subcellular localisation of CK1.2 but not for its kinase activity, whereas the deletion of the N-terminus leads to a dramatic decrease in CK1.2 abundance. In conclusion, our data on the localisation and regulation of Leishmania CK1.2 contribute to increase the knowledge on this essential kinase and get insights into its role in the parasite.

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Recent Advances in the Development of Casein Kinase 1 Inhibitors

Current Medicinal Chemistry ◽

10.2174/0929867327666200713185413 ◽

2020 ◽

Vol 27 ◽

Author(s):

Sha-Sha Li ◽

Yue-Hui Dong ◽

Zhao-Peng Liu

Keyword(s):

Membrane Trafficking ◽

Physicochemical Characterization ◽

Structural Features ◽

Casein Kinase ◽

Casein Kinase 1 ◽

Cellular Processes ◽

Damage Repair ◽

Recent Developments ◽

Cytoskeleton Dynamics ◽

Relationship Of

Background: The casein kinase 1 (CK1) family are involved in regulating many cellular processes including membrane trafficking, DNA damage repair, cytoskeleton dynamics, cytoskeleton maintenance and apoptosis. CK1 isoforms especially CK1δ and CK1ε have emerged as important therapeutic target for severe disorders such as Alzheimer’s disease (AD), amyotrophic lateral sclerosis (ALS), familial advanced sleep phase syndrome and cancer. Due to the importance of CK1 for the pathogenesis of disorders, there are great interests in the development of CK1 inhibitors. Method: Using SciFinder® as a tool, the publications about the biology of CK1 and the recent developments of CK1 inhibitors were surveyed with an exclusion on those published as patents. Results: This review presents the current state of knowledge on the development of CK1 inhibitors, including both the synthetic small molecular inhibitors that were divided into 7 categories according to structural features, and the natural compounds. An overview of the advancement of CK1 inhibitors was given, with the introduction of various existing CK1 inhibitors, their inhibitory activities, and the structure-activity relationships. Conclusion: Thorough physicochemical characterization and biological investigations, it is possible to understand structureactivity relationship of CK1 inhibitors, which will contribute to better design and discovery of potent and selective CK1 inhibitors as potential agents for severe disorders such as AD, ALS and cancer.

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E3 ubiquitin ligases

Essays in Biochemistry ◽

10.1042/bse0410015 ◽

2005 ◽

Vol 41 ◽

pp. 15-30 ◽

Cited By ~ 123

Author(s):

Helen C. Ardley ◽

Philip A. Robinson

Keyword(s):

Protein Complexes ◽

Loss Of Function ◽

Direct Role ◽

Cellular Processes ◽

Substrate Protein ◽

Protein Ubiquitination ◽

C Terminus ◽

Full Complement ◽

Spatio Temporal ◽

Eukaryotic Organisms

The selectivity of the ubiquitin–26 S proteasome system (UPS) for a particular substrate protein relies on the interaction between a ubiquitin-conjugating enzyme (E2, of which a cell contains relatively few) and a ubiquitin–protein ligase (E3, of which there are possibly hundreds). Post-translational modifications of the protein substrate, such as phosphorylation or hydroxylation, are often required prior to its selection. In this way, the precise spatio-temporal targeting and degradation of a given substrate can be achieved. The E3s are a large, diverse group of proteins, characterized by one of several defining motifs. These include a HECT (homologous to E6-associated protein C-terminus), RING (really interesting new gene) or U-box (a modified RING motif without the full complement of Zn2+-binding ligands) domain. Whereas HECT E3s have a direct role in catalysis during ubiquitination, RING and U-box E3s facilitate protein ubiquitination. These latter two E3 types act as adaptor-like molecules. They bring an E2 and a substrate into sufficiently close proximity to promote the substrate's ubiquitination. Although many RING-type E3s, such as MDM2 (murine double minute clone 2 oncoprotein) and c-Cbl, can apparently act alone, others are found as components of much larger multi-protein complexes, such as the anaphase-promoting complex. Taken together, these multifaceted properties and interactions enable E3s to provide a powerful, and specific, mechanism for protein clearance within all cells of eukaryotic organisms. The importance of E3s is highlighted by the number of normal cellular processes they regulate, and the number of diseases associated with their loss of function or inappropriate targeting.

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RNA G-Quadruplex Structures Mediate Gene Regulation in Bacteria

mBio ◽

10.1128/mbio.02926-19 ◽

2020 ◽

Vol 11 (1) ◽

Cited By ~ 4

Author(s):

Xiaolong Shao ◽

Weitong Zhang ◽

Mubarak Ishaq Umar ◽

Hei Yuen Wong ◽

Zijing Seng ◽

...

Keyword(s):

Gene Regulation ◽

Cell Envelope ◽

Bacterial Species ◽

Virulence Gene ◽

Content Type ◽

Cellular Processes ◽

Wide Range ◽

G Quadruplex ◽

Eukaryotic Organisms

ABSTRACT Guanine (G)-rich sequences in RNA can fold into diverse RNA G-quadruplex (rG4) structures to mediate various biological functions and cellular processes in eukaryotic organisms. However, the presence, locations, and functions of rG4s in prokaryotes are still elusive. We used QUMA-1, an rG4-specific fluorescent probe, to detect rG4 structures in a wide range of bacterial species both in vitro and in live cells and found rG4 to be an abundant RNA secondary structure across those species. Subsequently, to identify bacterial rG4 sites in the transcriptome, the model Escherichia coli strain and a major human pathogen, Pseudomonas aeruginosa, were subjected to recently developed high-throughput rG4 structure sequencing (rG4-seq). In total, 168 and 161 in vitro rG4 sites were found in E. coli and P. aeruginosa, respectively. Genes carrying these rG4 sites were found to be involved in virulence, gene regulation, cell envelope synthesis, and metabolism. More importantly, biophysical assays revealed the formation of a group of rG4 sites in mRNAs (such as hemL and bswR), and they were functionally validated in cells by genetic (point mutation and lux reporter assays) and phenotypic experiments, providing substantial evidence for the formation and function of rG4s in bacteria. Overall, our study uncovers important regulatory functions of rG4s in bacterial pathogenicity and metabolic pathways and strongly suggests that rG4s exist and can be detected in a wide range of bacterial species. IMPORTANCE G-quadruplex in RNA (rG4) mediates various biological functions and cellular processes in eukaryotic organisms. However, the presence, locations, and functions of rG4 are still elusive in prokaryotes. Here, we found that rG4 is an abundant RNA secondary structure across a wide range of bacterial species. Subsequently, the transcriptome-wide rG4 structure sequencing (rG4-seq) revealed that the model E. coli strain and a major human pathogen, P. aeruginosa, have 168 and 161 in vitro rG4 sites, respectively, involved in virulence, gene regulation, cell envelope, and metabolism. We further verified the regulatory functions of two rG4 sites in bacteria (hemL and bswR). Overall, this finding strongly suggests that rG4s play key regulatory roles in a wide range of bacterial species.

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Creating a customized intracellular niche: subversion of host cell signaling byLegionellatype IV secretion system effectors

Canadian Journal of Microbiology ◽

10.1139/cjm-2015-0166 ◽

2015 ◽

Vol 61 (9) ◽

pp. 617-635 ◽

Cited By ~ 23

Author(s):

Ernest C. So ◽

Corinna Mattheis ◽

Edward W. Tate ◽

Gad Frankel ◽

Gunnar N. Schroeder

Keyword(s):

Host Cell ◽

Legionella Pneumophila ◽

Current Knowledge ◽

Secretion System ◽

Effector Proteins ◽

Cellular Processes ◽

Type Iv ◽

Open Questions ◽

Exact Function ◽

Wide Range

The Gram-negative facultative intracellular pathogen Legionella pneumophila infects a wide range of different protozoa in the environment and also human alveolar macrophages upon inhalation of contaminated aerosols. Inside its hosts, it creates a defined and unique compartment, termed the Legionella-containing vacuole (LCV), for survival and replication. To establish the LCV, L. pneumophila uses its Dot/Icm type IV secretion system (T4SS) to translocate more than 300 effector proteins into the host cell. Although it has become apparent in the past years that these effectors subvert a multitude of cellular processes and allow Legionella to take control of host cell vesicle trafficking, transcription, and translation, the exact function of the vast majority of effectors still remains unknown. This is partly due to high functional redundancy among the effectors, which renders conventional genetic approaches to elucidate their role ineffective. Here, we review the current knowledge about Legionella T4SS effectors, highlight open questions, and discuss new methods that promise to facilitate the characterization of T4SS effector functions in the future.

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Pathogens and polymers: Microbe–host interactions illuminate the cytoskeleton

The Journal of Cell Biology ◽

10.1083/jcb.201103148 ◽

2011 ◽

Vol 195 (1) ◽

pp. 7-17 ◽

Cited By ~ 133

Author(s):

Cat M. Haglund ◽

Matthew D. Welch

Keyword(s):

Host Cell ◽

Membrane Trafficking ◽

Cell Biology ◽

Cytoskeletal Proteins ◽

Intracellular Pathogens ◽

Regulatory Pathways ◽

Host Interactions ◽

Cellular Processes ◽

Cytoskeletal Function ◽

Common Target

Intracellular pathogens subvert the host cell cytoskeleton to promote their own survival, replication, and dissemination. Study of these microbes has led to many discoveries about host cell biology, including the identification of cytoskeletal proteins, regulatory pathways, and mechanisms of cytoskeletal function. Actin is a common target of bacterial pathogens, but recent work also highlights the use of microtubules, cytoskeletal motors, intermediate filaments, and septins. The study of pathogen interactions with the cytoskeleton has illuminated key cellular processes such as phagocytosis, macropinocytosis, membrane trafficking, motility, autophagy, and signal transduction.

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Activity and Trafficking of Copper-Transporting ATPases in Tumor Development and Defense against Platinum-Based Drugs

Cells ◽

10.3390/cells8091080 ◽

2019 ◽

Vol 8 (9) ◽

pp. 1080 ◽

Cited By ~ 13

Author(s):

Raffaella Petruzzelli ◽

Roman S. Polishchuk

Keyword(s):

Tumor Cells ◽

Membrane Trafficking ◽

Tumor Development ◽

Current Data ◽

Malignant Cells ◽

Potential Toxicity ◽

Cellular Processes ◽

Wide Range ◽

Cu Homeostasis

Membrane trafficking pathways emanating from the Golgi regulate a wide range of cellular processes. One of these is the maintenance of copper (Cu) homeostasis operated by the Golgi-localized Cu-transporting ATPases ATP7A and ATP7B. At the Golgi, these proteins supply Cu to newly synthesized enzymes which use this metal as a cofactor to catalyze a number of vitally important biochemical reactions. However, in response to elevated Cu, the Golgi exports ATP7A/B to post-Golgi sites where they promote sequestration and efflux of excess Cu to limit its potential toxicity. Growing tumors actively consume Cu and employ ATP7A/B to regulate the availability of this metal for oncogenic enzymes such as LOX and LOX-like proteins, which confer higher invasiveness to malignant cells. Furthermore, ATP7A/B activity and trafficking allow tumor cells to detoxify platinum (Pt)-based drugs (like cisplatin), which are used for the chemotherapy of different solid tumors. Despite these noted activities of ATP7A/B that favor oncogenic processes, the mechanisms that regulate the expression and trafficking of Cu ATPases in malignant cells are far from being completely understood. This review summarizes current data on the role of ATP7A/B in the regulation of Cu and Pt metabolism in malignant cells and outlines questions and challenges that should be addressed to understand how ATP7A and ATP7B trafficking mechanisms might be targeted to counteract tumor development.

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Cytokinin and Ethylene Cell Signaling Pathways from Prokaryotes to Eukaryotes

Cells ◽

10.3390/cells9112526 ◽

2020 ◽

Vol 9 (11) ◽

pp. 2526

Author(s):

Baptiste Bidon ◽

Samar Kabbara ◽

Vincent Courdavault ◽

Gaëlle Glévarec ◽

Audrey Oudin ◽

...

Keyword(s):

Signaling Pathways ◽

Signaling Molecules ◽

Terrestrial Plants ◽

Cellular Processes ◽

Wide Range ◽

Component Systems ◽

Genes Encoding ◽

Long Time ◽

Two Component Systems ◽

Eukaryotic Organisms

Cytokinins (CKs) and ethylene (ET) are among the most ancient organic chemicals on Earth. A wide range of organisms including plants, algae, fungi, amoebae, and bacteria use these substances as signaling molecules to regulate cellular processes. Because of their ancestral origin and ubiquitous occurrence, CKs and ET are also considered to be ideal molecules for inter-kingdom communication. Their signal transduction pathways were first historically deciphered in plants and are related to the two-component systems, using histidine kinases as primary sensors. Paradoxically, although CKs and ET serve as signaling molecules in different kingdoms, it has been supposed for a long time that the canonical CK and ET signaling pathways are restricted to terrestrial plants. These considerations have now been called into question following the identification over recent years of genes encoding CK and ET receptor homologs in many other lineages within the tree of life. These advances shed new light on the dissemination and evolution of these hormones as both intra- and inter-specific communication molecules in prokaryotic and eukaryotic organisms.

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Calmodulin controls organization of the actin cytoskeleton via regulation of phosphatidylinositol (4,5)-bisphosphate synthesis in Saccharomyces cerevisiae

Biochemical Journal ◽

10.1042/bj20020429 ◽

2002 ◽

Vol 366 (3) ◽

pp. 945-951 ◽

Cited By ~ 33

Author(s):

Sylvane DESRIVIÈRES ◽

Frank T. COOKE ◽

Helena MORALES-JOHANSSON ◽

Peter J. PARKER ◽

Michael N. HALL

Keyword(s):

Saccharomyces Cerevisiae ◽

Actin Cytoskeleton ◽

Membrane Trafficking ◽

Binding Protein ◽

Temperature Sensitive ◽

Cellular Processes ◽

Wide Range ◽

Phosphatidylinositol 4 ◽

Calmodulin Mutant

Phosphoinositides regulate a wide range of cellular processes, including proliferation, survival, cytoskeleton remodelling and membrane trafficking, yet the mechanisms controlling the kinases, phosphatases and lipases that modulate phosphoinositide levels are poorly understood. In the present study, we describe a mechanism controlling MSS4, the sole phosphatidylinositol (4)-phosphate 5-kinase in Saccharomyces cerevisiae. Mutations in MSS4 and CMD1, encoding the small Ca2+-binding protein calmodulin, confer similar phenotypes, including loss of viability and defects in endocytosis and in organization of the actin cytoskeleton. Overexpression of MSS4 suppresses the growth and actin defects of cmd1-226, a temperature-sensitive calmodulin mutant which is defective in the organization of the actin cytoskeleton. Finally, the cmd1-226 mutant exhibits reduced levels of phosphatidylinositol (4,5)-bisphosphate. These findings suggest that calmodulin positively controls MSS4 activity and thereby the actin cytoskeleton.

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Interaction of Plasmodium falciparum Casein kinase 1 (PfCK1) with components of host cell protein trafficking machinery

10.1101/617571 ◽

2019 ◽

Author(s):

Mitchell B Batty ◽

Ralf B Schittenhelm ◽

Christian Doerig ◽

Jose Garcia-Bustos

Keyword(s):

Plasmodium Falciparum ◽

Membrane Trafficking ◽

Casein Kinase ◽

Cell Protein ◽

Host Proteins ◽

Extracellular Medium ◽

Casein Kinase 1 ◽

Rbc Membrane ◽

Stage Of Development ◽

Higher Eukaryotes

AbstractDuring infection, the Plasmodium falciparum casein kinase 1 (PfCK1) is secreted to the extracellular medium and appears on the RBC membrane during trophozoite stage of development. We attempted to identify a mechanism that describes the secretion of PfCK1 and its appearance on the RBC membrane and suspected a mechanism involving multiple host proteins may be utilised. Indeed, we found that the host proteins GTPase-activating protein and Vps9 domain-containing protein (GAPVD1) and Sorting nexin 22 (SNX22), which have described functions in membrane trafficking in higher eukaryotes, consistently co-purify with PfCK1 suggesting the parasite utilises trafficking pathways previously thought to be inactive in RBCs. Further, reciprocal immunoprecipitation experiments with GAPVD1 identified parasite proteins suggestive of a recycling pathway hitherto only described in higher eukaryotes to recycle membrane proteins. Thus, we have identified components of a trafficking pathway involving parasite proteins that act in concert with host proteins which we hypothesise coordinate the trafficking of PfCK1 during infection.

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Phosphoinositide 3-kinase signalling pathways

Journal of Cell Science ◽

10.1242/jcs.114.8.1439 ◽

2001 ◽

Vol 114 (8) ◽

pp. 1439-1445 ◽

Cited By ~ 13

Author(s):

D.A. Cantrell

Keyword(s):

Tyrosine Kinases ◽

Cell Cycle Progression ◽

Subcellular Localisation ◽

Nucleotide Exchange ◽

Cellular Processes ◽

Signalling Molecule ◽

Inositol Phospholipids ◽

Wide Range ◽

Ph Domains ◽

Phosphoinositide 3 Kinase

Phosphoinositide 3-kinases (PI3Ks) phosphorylate the 3′-OH position of the inositol ring of inositol phospholipids, producing three lipid products: PtdIns(3)P, PtdIns(3,4)P(2) and PtdIns(3,4,5)P(3). These lipids bind to the pleckstrin homology (PH) domains of proteins and control the activity and subcellular localisation of a diverse array of signal transduction molecules. Three major classes of signalling molecule are regulated by binding of D-3 phosphoinositides to PH domains: guanine-nucleotide-exchange proteins for Ρ family GTPases, the TEC family tyrosine kinases such as BTK and ITK in B and T lymphocytes, respectively, and the AGC superfamily of serine/threonine protein kinases. These molecules are activated by a variety of extracellular stimuli and have been implicated in a wide range of cellular processes, including cell cycle progression, cell growth, cell motility, cell adhesion and cell survival.

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