scholarly journals Phosphorylation-dependent routing of RLP44 towards brassinosteroid or phytosulfokine signalling

2019 ◽  
Author(s):  
Borja Garnelo Gómez ◽  
Rosa Lozano-Durán ◽  
Sebastian Wolf
Keyword(s):  
Intracellular Localization ◽  
Interaction Network ◽  
Post Translational Modification ◽  
Common Component ◽  
Receptor Proteins ◽  
Surface Receptors ◽  
Receptor Complexes ◽  
Phosphorylation Pattern ◽  
Membrane Phosphorylation ◽  
Status Analysis

AbstractPlants rely on a complex network of cell surface receptors to integrate developmental and environmental cues into behaviour adapted to the conditions. The largest group of these receptors, leucine-rich repeat receptor-like kinases, form a complex interaction network that is modulated and extended by receptor-like proteins. This raises the question of how specific outputs can be generated when receptor proteins are engaged in a plethora of promiscuous interactions. RECEPTOR-LIKE PROTEIN 44 acts to promote brassinosteroid and phytosulfokine signalling, which orchestrate a wide variety of cellular responses. However, it is unclear how these activities are coordinated. Here, we show that RLP44 is phosphorylated in its highly conserved C-terminal cytosolic tail and that this post-translational modification governs its subcellular localization. RLP44 variants in which phosphorylation is blocked enter endocytosis prematurely, leading to an almost entirely intracellular localization, whereas mimicking phosphorylation results in preferential RLP44 localization at the plasma membrane. Phosphorylation is crucial for regulating RLP44’s interaction with the brassinosteroid receptor BRASSINOSTEROID INSENSITIVE 1, and thus its function in BR signalling activation. In contrast, the interaction of RLP44 with PHYTOSULFOKINE RECEPTOR 1 is not affected by its phospho-status. Analysis of the contribution of individual amino acid modifications suggests that routing of RLP44 to its target receptor complexes is controlled by its phosphorylation pattern, providing a framework to understand how a common component of different receptor complexes can get specifically engaged in a particular signalling pathway.

scholarly journals Phosphorylation-dependent routing of RLP44 towards brassinosteroid or phytosulfokine signalling

2021 ◽  
Author(s):  
Borja Garnelo Gómez ◽  
Eleonore Holzwart ◽  
Chaonan Shi ◽  
Rosa Lozano-Durán ◽  
Sebastian Wolf
Keyword(s):  
Mutational Analysis ◽  
Interaction Network ◽  
Cellular Responses ◽  
Environmental Cues ◽  
Post Translational Modification ◽  
Common Component ◽  
Receptor Proteins ◽  
Surface Receptors ◽  
Receptor Complexes ◽  
Associated Functions

Plants rely on cell surface receptors to integrate developmental and environmental cues into behaviour adapted to the conditions. The largest group of these receptors, leucine-rich repeat receptor-like kinases, form a complex interaction network that is modulated and extended by receptor-like proteins. This raises the question of how specific outputs can be generated when receptor proteins are engaged in a plethora of promiscuous interactions. RECEPTOR-LIKE PROTEIN 44 (RLP44) acts to promote both brassinosteroid and phytosulfokine signalling, which orchestrate diverse cellular responses. However, it's unclear how these activities are coordinated. Here, we show that RLP44 is phosphorylated in its highly conserved cytosolic tail and that this post-translational modification governs its subcellular localization. Whereas phosphorylation is essential for brassinosteroid-associated functions of RLP44, its role in phytosulfokine signalling is not affected by phospho-status. Detailed mutational analysis suggests that phospho-charge, rather than modification of individual amino acids determines routing of RLP44 to its target receptor complexes, providing a framework to understand how a common component of different receptor complexes can get specifically engaged in a particular signalling pathway.

Tachyphylaxis to the vasopressor effects of endothelin in rat aortic rings

1993 ◽  
Vol 264 (2) ◽  
pp. H352-H356 ◽  
Author(s):  
S. M. Hollenberg ◽  
J. H. Shelhamer ◽  
R. E. Cunnion
Keyword(s):  
Endothelial Cells ◽  
Systemic Vascular Resistance ◽  
Vascular Resistance ◽  
Pressor Effect ◽  
Endothelin Receptor ◽  
Surface Receptors ◽  
Receptor Complexes ◽  
High Affinity ◽  
Potent Vasoconstrictor ◽  
Vasoconstrictor Peptide

Endothelin-1 (ET-1), a potent vasoconstrictor peptide released by endothelial cells, binds with high affinity to surface receptors and is highly resistant to dissociation. We observed tachyphylaxis to the pressor effects of a second application of ET-1 in rat aortic rings and investigated the mechanism of this effect. Developed tension increased progressively with doses of ET-1 ranging from 1 to 500 nM (P < 0.001), and tensions with rechallenge were correspondingly decreased (P < 0.001). In response to 500 nM ET-1, tension increased 1,599 +/- 72 (SE) mg/mg ring wt. Rechallenge with 500 nM ET-1 led to contraction of only 33 +/- 40 mg/mg ring wt. Tachyphylaxis was seen up to 6 h after initial challenge. Pretreatment with nicardipine, lidoflazine, nitroglycerin, and sphingosine did not affect tachyphylaxis. Pretreatment with 500 microM dansylcadaverine (an inhibitor of endothelin internalization) markedly inhibited ET-1-induced contraction and also inhibited tachyphylaxis to ET-1. Further studies with radiolabeled ET-1 suggested that subsequent ET-1 binding is markedly decreased after an initial ET-1 challenge. Dansylcadaverine inhibited ET-1 internalization and also inhibited the decreased binding seen with ET-1 rechallenge. Rat aortic rings demonstrate tachyphylaxis to the pressor effect of a second dose of ET-1. The mechanism appears to be related to binding and subsequent internalization of endothelin-receptor complexes. This effect suggests a possible mechanism for sustained decreases in systemic vascular resistance.

scholarly journals Down-Regulation of Cell Surface Receptors Is Modulated by Polar Residues within the Transmembrane Domain

2000 ◽  
Vol 11 (8) ◽  
pp. 2643-2655 ◽  
Author(s):  
Lolita Zaliauskiene ◽  
Sunghyun Kang ◽  
Christie G. Brouillette ◽  
Jacob Lebowitz ◽  
Ramin B. Arani ◽  
...  
Keyword(s):  
Cell Surface ◽  
Transmembrane Domain ◽  
Gradient Centrifugation ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Surface Proteins ◽  
Down Regulation ◽  
Surface Receptors ◽  
Receptor Complexes ◽  
Polar Residues

How recycling receptors are segregated from down-regulated receptors in the endosome is unknown. In previous studies, we demonstrated that substitutions in the transferrin receptor (TR) transmembrane domain (TM) convert the protein from an efficiently recycling receptor to one that is rapidly down regulated. In this study, we demonstrate that the “signal” within the TM necessary and sufficient for down-regulation is Thr11Gln17Thr19 (numbering in TM). Transplantation of these polar residues into the wild-type TR promotes receptor down-regulation that can be demonstrated by changes in protein half-life and in receptor recycling. Surprisingly, this modification dramatically increases the TR internalization rate as well (∼79% increase). Sucrose gradient centrifugation and cross-linking studies reveal that propensity of the receptors to self-associate correlates with down-regulation. Interestingly, a number of cell surface proteins that contain TM polar residues are known to be efficiently down-regulated, whereas recycling receptors for low-density lipoprotein and transferrin conspicuously lack these residues. Our data, therefore, suggest a simple model in which specific residues within the TM sequences dramatically influence the fate of membrane proteins after endocytosis, providing an alternative signal for down-regulation of receptor complexes to the well-characterized cytoplasmic tail targeting signals.

scholarly journals A conserved regulatory module regulates receptor kinase signaling in immunity and development

2021 ◽  
Author(s):  
Thomas A. DeFalco ◽  
Pauline Anne ◽  
Sean R. James ◽  
Andrew Willoughby ◽  
Oliver Johanndrees ◽  
...  
Keyword(s):  
Cell Surface ◽  
Cellular Responses ◽  
Receptor Signaling ◽  
Receptor Kinase ◽  
Surface Receptors ◽  
Receptor Complexes ◽  
Regulatory Circuit ◽  
Regulatory Module ◽  
Molecular Patterns ◽  
Receptor Kinase Signaling

ABSTRACTLigand recognition by cell-surface receptors underlies development and immunity in both animals and plants. Modulating receptor signaling is critical for appropriate cellular responses but the mechanisms ensuring this are poorly understood. Here, we show that signaling by plant receptors for pathogen-associated molecular patterns (PAMPs) in immunity and CLAVATA3/EMBRYO SURROUNDING REGION-RELATED peptides (CLEp) in development employ a similar regulatory module. In the absence of ligand, signaling is dampened through association with specific type-2C protein phosphatases (PP2Cs). Upon activation, PAMP and CLEp receptors phosphorylate divergent cytosolic kinases, which, in turn, phosphorylate the phosphatases, thereby promoting their release from the receptor complexes. Our work reveals a regulatory circuit shared between immune and developmental receptor signaling, which may have broader important implications for plant receptor kinase-mediated signaling in general.

Conserved E1B-55K SUMOylation in different human adenovirus species is a potent regulator of intracellular localization

2021 ◽  
Author(s):  
Viktoria Kolbe ◽  
Wing H. Ip ◽  
Lisa Kieweg-Thompson ◽  
Judith Lang ◽  
Julia Gruhne ◽  
...  
Keyword(s):  
Cell Transformation ◽  
Intracellular Localization ◽  
Human Adenovirus ◽  
Lysine Residue ◽  
Future Research ◽  
Post Translational Modification ◽  
Cellular Effects ◽  
Sumo Conjugation ◽  
Functional Consequences ◽  
Organ Tropism

Over the past decades, studies on the biology of human adenoviruses (HAdVs) mainly focused on the HAdV prototype species C type 5 (HAdV-C5) and revealed fundamental molecular insights into mechanisms of viral replication and viral cell transformation. Recently, other HAdV species are gaining more and more attention in the field. Reports on large E1B proteins (E1B-55K) from different HAdV species showed that these multifactorial proteins possess strikingly different features along with highly conserved functions. In this work, we identified potential SUMO-conjugation motifs (SCMs) in E1B-55K proteins from HAdV species A to F. Mutational inactivation of these SCMs demonstrated that HAdV E1B-55K proteins are SUMOylated at a single lysine residue that is highly conserved among HAdV species B to E. Moreover, we provide evidence that E1B-55K SUMOylation is a potent regulator of intracellular localization and p53-mediated transcription in most HAdV species. We also identified a lysine residue at position 101 (K101), which is unique to HAdV-C5 E1B-55K and specifically regulates its SUMOylation and nucleo-cytoplasmic shuttling. Our findings reveal important new aspects on HAdV E1B-55K proteins and suggest that different E1B-55K species possess conserved SCMs while their SUMOylation has divergent cellular effects during infection. Importance E1B-55K is a multifunctional adenoviral protein and its functions are highly regulated by SUMOylation. Although functional consequences of SUMOylated HAdV-C5 E1B-55K are well studied, we lack information on the effects of SUMOylation on homologous E1B-55K proteins from other HAdV species. Here, we show that SUMOylation is a conserved post-translational modification in most of the E1B-55K proteins, similar to what we know about HAdV-C5 E1B-55K. Moreover, we identify subcellular localization and regulation of p53-dependent transcription as highly conserved SUMOylation-regulated E1B-55K functions. Thus, our results highlight how HAdV proteins might have evolved in different HAdV species with conserved domains involved in virus replication and differing alternative functions and interactions with the host cell machinery. Future research will link these differences and similarities to the diverse pathogenicity and organ tropism of the different HAdV species.

scholarly journals Developing Practical Therapeutic Strategies that Target Protein SUMOylation

2019 ◽  
Vol 20 (9) ◽  
pp. 960-969 ◽  
Author(s):  
Olivia F. Cox ◽  
Paul W. Huber
Keyword(s):  
Birth Defects ◽  
Inflammatory Disease ◽  
Intracellular Localization ◽  
Specific Protein ◽  
Therapeutic Strategies ◽  
Biological Processes ◽  
Post Translational Modification ◽  
Protein Activity ◽  
Multiple Components ◽  
Congenital Birth Defects

Post-translational modification by small ubiquitin-like modifier (SUMO) has emerged as a global mechanism for the control and integration of a wide variety of biological processes through the regulation of protein activity, stability and intracellular localization. As SUMOylation is examined in greater detail, it has become clear that the process is at the root of several pathologies including heart, endocrine, and inflammatory disease, and various types of cancer. Moreover, it is certain that perturbation of this process, either globally or of a specific protein, accounts for many instances of congenital birth defects. In order to be successful, practical strategies to ameliorate conditions due to disruptions in this post-translational modification will need to consider the multiple components of the SUMOylation machinery and the extraordinary number of proteins that undergo this modification.

scholarly journals Combinatorial Inhibition of Cell Surface Receptors Using Dual Aptamer-Functionalized Nanoconstructs for Cancer Treatment

Pharmaceutics ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 689
Author(s):  
Hyojin Lee ◽  
Tae Hee Kim ◽  
Daechan Park ◽  
Mihue Jang ◽  
Justin J. Chung ◽  
...  
Keyword(s):  
Membrane Receptors ◽  
Local Concentration ◽  
Cellular Functions ◽  
Receptor Proteins ◽  
Surface Receptors ◽  
Dual Targeting ◽  
Therapeutic Value ◽  
Anti Cancer ◽  
Targeting Strategy ◽  
Poor Efficacy

Membrane receptors overexpressed in diseased states are considered novel therapeutic targets. However, the single targeting approach faces several fundamental issues, such as poor efficacy, resistance, and toxicity. Here, we report a dual-targeting strategy to enhance anti-cancer efficacy via synergistic proximity interactions between therapeutics and two receptor proteins. Importantly, we report the first finding of an interaction between c-Met and nucleolin and demonstrate the therapeutic value of targeting the interaction between them. Bispecific nanocarriers densely grafted with anti-c-Met and -nucleolin aptamer increased the local concentration of aptamers at the target sites, in addition to inducing target receptor clustering. It was also demonstrated that the simultaneous targeting of c-Met and nucleolin inhibited the cellular functions of the receptors and increased anti-cancer efficacy by altering the cell cycle. Our findings pave the way for the development of an effective combinatorial treatment based on nanoconstruct-mediated interaction between receptors.

scholarly journals Specificity, versatility, and control of TGF-β family signaling

2019 ◽  
Vol 12 (570) ◽  
pp. eaav5183 ◽  
Author(s):  
Rik Derynck ◽  
Erine H. Budi
Keyword(s):  
Mammalian Cells ◽  
Transforming Growth Factor ◽  
Transforming Growth Factor Β ◽  
Smad Signaling ◽  
Surface Receptors ◽  
Cell Lineages ◽  
Receptor Complexes ◽  
Signaling Mechanisms ◽  
Dual Specificity ◽  
And Control

Encoded in mammalian cells by 33 genes, the transforming growth factor–β (TGF-β) family of secreted, homodimeric and heterodimeric proteins controls the differentiation of most, if not all, cell lineages and many aspects of cell and tissue physiology in multicellular eukaryotes. Deregulation of TGF-β family signaling leads to developmental anomalies and disease, whereas enhanced TGF-β signaling contributes to cancer and fibrosis. Here, we review the fundamentals of the signaling mechanisms that are initiated upon TGF-β ligand binding to its cell surface receptors and the dependence of the signaling responses on input from and cooperation with other signaling pathways. We discuss how cells exquisitely control the functional presentation and activation of heteromeric receptor complexes of transmembrane, dual-specificity kinases and, thus, define their context-dependent responsiveness to ligands. We also introduce the mechanisms through which proteins called Smads act as intracellular effectors of ligand-induced gene expression responses and show that the specificity and impressive versatility of Smad signaling depend on cross-talk from other pathways. Last, we discuss how non-Smad signaling mechanisms, initiated by distinct ligand-activated receptor complexes, complement Smad signaling and thus contribute to cellular responses.

scholarly journals FAK and PYK2 are specifically associated with the activated phagocytic receptor complexes from human U937 cells.

2021 ◽  
Author(s):  
Marwan G. AbidAlthagafi
Keyword(s):  
Cell Surface ◽  
Tyrosine Kinases ◽  
Laser Scanning ◽  
Surface Proteins ◽  
Protein Tyrosine Kinases ◽  
Macrophage Cell ◽  
Protein Tyrosine ◽  
Surface Receptors ◽  
Receptor Complexes

The innate immune system is the first shield against foreign attack inside the human body, and it is usually carried out with phagocytosis. An essential macrophage cell surface protein is the Fc receptor which contributes to the engulfment of unknown antigens. One of the important members of Fc receptors is the gamma receptor that binds to the immunoglobulin G (IgG) ligand. Another key receptor in this study is the CD36 receptor, which plays a crucial role in the progression of atherosclerosis, the hardening of arteries, with its ligand oxidized low-density lipoprotein (OxLDL). In this report, protein tyrosine kinase enzymes have been detected in the involvement of receptor complexes with human U937 macrophages, specifically PTK2 and PTK2b genes. Protein tyrosine kinases were known to promote cell migration as a main player in intracellular signal transduction cascades in relation to extracellular stimuli. Cell surface proteins are essential for the immunization of various diseases; yet, the molecular machinery of surface receptors remains unclear. This research primarily examined the dynamic nature of protein tyrosine kinases in an ongoing investigation of macrophage cell surface receptors, particularly the role of Fc γ and CD36 receptors with their ligands IgG and oxLDL coated beads in phagocytosis. Our report demonstrates a novel role of PTK2 and PTK2b functions in relation to U937 CD36-mediated phagocytosis. The Phagocytic efficiency of U937 macrophages was analyzed using laser scanning confocal microscope after silencing the cells with siRNA followed by quantitative counting of phagocytosis. The PF drug FAK inhibitor was also introduced to compare the phagocytic efficiency of siRNA cells.

The small GTP-binding protein RacG regulates uroid formation in the protozoan parasite Entamoeba histolytica

1998 ◽  
Vol 111 (12) ◽  
pp. 1729-1739 ◽  
Author(s):  
N. Guillen ◽  
P. Boquet ◽  
P. Sansonetti
Keyword(s):  
Cell Polarity ◽  
Entamoeba Histolytica ◽  
Mammalian Cells ◽  
Protozoan Parasite ◽  
Small Gtpases ◽  
Eukaryotic Cells ◽  
Protein Activity ◽  
Surface Receptors ◽  
Receptor Complexes ◽  
Murine Fibroblasts

Entamoeba histolytica is a protozoan parasite that invades human intestine leading to ulceration and destruction of tissue. Amoebic movement and phagocytosis of human cells is accompanied by characteristic changes in cell morphology. Amoebae become polarized, developing a frontal pseudopod and a well-defined rear zone of membrane accumulation designated the uroid. In motile eukaryotic cells, a phenomenon that contributes to movement is the capping of receptors at the cell surface. During the capping process, E. histolytica concentrates ligand-receptor complexes in the uroid. Interestingly, some of these surface receptors are involved in the survival of the parasite. While looking for regulators of capping and uroid formation, we identified RacG, an E. histolytica protein that is homologous to human Rac1. This protein belongs to the Rac subfamily of small GTPases implicated in interactions between the actin cytoskeleton and the membrane of mammalian cells. Cloning of the EhracG gene and analysis of the protein activity either in murine fibroblasts or in E. histolytica revealed that EhRacG induces a characteristic Rac phenotype. When expressed in amoebae, an EhRacG-V12 mutant protein not only deregulated cell polarity, but also caused a defect in cytokinesis. Analysis of the cytoskeleton in amoebae bearing this mutant revealed that F-actin concentrated at the periphery of the cell. In addition, the number and localization of uroids were modified. These results suggest a role for EhRacG in amoebic morphogenesis and cytokinesis.

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