Regulation of the serotonin transporter by interacting proteins

2001 ◽  
Vol 29 (6) ◽  
pp. 722-728 ◽  
Author(s):  
J. Haase ◽  
A.-M. Killian ◽  
F. Magnani ◽  
C. Williams
Keyword(s):  
Serotonin Transporter ◽  
Critical Role ◽  
Regulatory Protein ◽  
Receptor Protein ◽  
Glutathione S Transferase ◽  
Yeast Two Hybrid System ◽  
Glycine Transporters ◽  
Protein Receptor ◽  
Brain Cdna Library ◽  
5 Ht Uptake

The serotonin transporter (SERT) plays a critical role in the maintenance of normal neurotransmission by serotonin [5-hydroxytryptamine (5-HT)]. Recent evidence suggests that SERT and other neurotransmitter transporters are tightly regulated. Activation of protein kinase C results in a decrease in SERT-mediated 5-HT uptake, which is due to an internalization of the transporter. However, to date little is known about the mechanism and proteins involved in the down-regulation of the transporter. One candidate SERT-regulatory protein is the SNARE (soluble N-ethylmaleimide-sensitive factor-attachment protein receptor) protein, syntaxin 1A (Syn1A), which has recently been implicated in the regulation of ion channels as well as the SERT-related γ-aminobutyric acid- and glycine-transporters. Using 5-HT uptake assays, confocal microscopy and glutathione S-transferase (GST) pull-down assays we showed that Syn1A also interacts with SERT and alters the subcellular localization of the transporter, resulting in a reduction of 5-HT transport. In addition, we have used the yeast two-hybrid system to search for novel regulatory proteins that interact with the cytoplasmic N-terminal domain of SERT. By screening rat brain cDNA library we have identified six potential SERT-binding proteins. Here we also present progress towards the elucidation of the biological relevance of these proteins and their potential role for the regulation of the serotonin transporter.

scholarly journals Effects of novel maturity-onset diabetes of the young (MODY)-associated mutations on glucokinase activity and protein stability

2005 ◽  
Vol 393 (1) ◽  
pp. 389-396 ◽  
Author(s):  
María Galán ◽  
Olivier Vincent ◽  
Isabel Roncero ◽  
Sharona Azriel ◽  
Pedro Boix-Pallares ◽  
...  
Keyword(s):  
Protein Stability ◽  
Glucose Sensor ◽  
Critical Role ◽  
Regulatory Protein ◽  
Missense Mutations ◽  
Maturity Onset Diabetes ◽  
Glutathione S Transferase ◽  
Enzymatic Assays ◽  
Onset Diabetes ◽  
Healthy Control

Glucokinase acts as the pancreatic glucose sensor and plays a critical role in the regulation of insulin secretion by the β-cell. Heterozygous mutations in the glucokinase-encoding GCK gene, which result in a reduction of the enzymatic activity, cause the monogenic form of diabetes, MODY2 (maturity-onset diabetes of the young 2). We have identified and functionally characterized missense mutations in the GCK gene in diabetic families that result in protein mutations Leu165→Phe, Glu265→Lys and Thr206→Met. The first two are novel GCK mutations that co-segregate with the diabetes phenotype in their respective families and are not found in more than 50 healthy control individuals. In order to measure the biochemical effects of these missense mutations on glucokinase activity, we bacterially expressed and affinity-purified islet human glucokinase proteins carrying the respective mutations and fused to GST (glutathione S-transferase). Enzymatic assays on the recombinant proteins revealed that mutations Thr206→Met and Leu165→Phe strongly affect the kinetic parameters of glucokinase, in agreement with the localization of both residues close to the active site of the enzyme. In contrast, mutation Glu265→Lys, which has a weaker effect on the kinetics of glucokinase, strongly affects the protein stability, suggesting a possible structural defect of this mutant protein. Finally, none of the mutations tested appears to affect the interaction of gluco-kinase with the glucokinase regulatory protein in the yeast two-hybrid system.

scholarly journals Inhibition of Glycine Re-Uptake: A Potential Approach for Treating Pain by Augmenting Glycine-Mediated Spinal Neurotransmission and Blunting Central Nociceptive Signaling

Biomolecules ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 864
Author(s):  
Christopher L. Cioffi
Keyword(s):  
Spinal Cord ◽  
Dorsal Horn ◽  
Therapeutic Potential ◽  
Opioid Analgesic ◽  
Critical Role ◽  
Analgesic Efficacy ◽  
Standard Of Care ◽  
Current Standard ◽  
Glycine Transporters ◽  
Pathological Pain

Among the myriad of cellular and molecular processes identified as contributing to pathological pain, disinhibition of spinal cord nociceptive signaling to higher cortical centers plays a critical role. Importantly, evidence suggests that impaired glycinergic neurotransmission develops in the dorsal horn of the spinal cord in inflammatory and neuropathic pain models and is a key maladaptive mechanism causing mechanical hyperalgesia and allodynia. Thus, it has been hypothesized that pharmacological agents capable of augmenting glycinergic tone within the dorsal horn may be able to blunt or block aberrant nociceptor signaling to the brain and serve as a novel class of analgesics for various pathological pain states. Indeed, drugs that enhance dysfunctional glycinergic transmission, and in particular inhibitors of the glycine transporters (GlyT1 and GlyT2), are generating widespread interest as a potential class of novel analgesics. The GlyTs are Na+/Cl−-dependent transporters of the solute carrier 6 (SLC6) family and it has been proposed that the inhibition of them presents a possible mechanism by which to increase spinal extracellular glycine concentrations and enhance GlyR-mediated inhibitory neurotransmission in the dorsal horn. Various inhibitors of both GlyT1 and GlyT2 have demonstrated broad analgesic efficacy in several preclinical models of acute and chronic pain, providing promise for the approach to deliver a first-in-class non-opioid analgesic with a mechanism of action differentiated from current standard of care. This review will highlight the therapeutic potential of GlyT inhibitors as a novel class of analgesics, present recent advances reported for the field, and discuss the key challenges associated with the development of a GlyT inhibitor into a safe and effective agent to treat pain.

scholarly journals PR-1-Like Protein as a Potential Target for the Identification of Fusarium oxysporum: An In Silico Approach

BioTech ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 8
Author(s):  
Olalekan Olanrewaju Bakare ◽  
Arun Gokul ◽  
Marshall Keyster
Keyword(s):  
Antimicrobial Peptides ◽  
Fusarium Oxysporum ◽  
In Silico ◽  
Crop Yields ◽  
Research Work ◽  
Receptor Protein ◽  
Economic Losses ◽  
Protein Receptor ◽  
Novel Biomarkers ◽  
Docking Interaction

Fusarium oxysporum remains one of the leading causes of economic losses and poor crop yields; its detection is strained due to its presentation in various morphological and physiological forms. This research work sought to identify novel biomarkers for the detection of Fusarium oxysporum using in silico approaches. Experimentally validated anti-Fusarium oxysporum antimicrobial peptides (AMPs) were used to construct a profile against Fusarium oxysporum. The performance and physicochemical parameters of these peptides were predicted. The gene for the Fusarium oxysporum receptor protein PR-1-like Protein, Fpr1, was identified and translated. The resulting protein model from the translation was then validated. The anti-Fusarium oxysporum AMPs and Fusarium oxysporum receptor protein 3-D structures were characterized, and their docking interaction analyses were carried out. The HMMER in silico tool identified novel anti-Fusarium oxysporum antimicrobial peptides with good performance in terms of accuracy, sensitivity, and specificity. These AMPs also displayed good physicochemical properties and bound with greater affinity to Fusarium oxysporum protein receptor PR-1-like Protein. The tendency of these AMPs to precisely detect Fusarium oxysporum PR-1-like Protein, Fpr1, would justify their use for the identification of the fungus. This study would enhance and facilitate the identification of Fusarium oxysporum to reduce problems associated with poor crop yield, economic losses, and decreased nutritional values of plants to keep up with the growing population.

Compared with SARS-CoV2 wild type's spike protein, the SARS-CoV2 omicron's receptor binding motif has adopted a more SARS-CoV1 and/or bat/civet-like structure.

2021 ◽  
Author(s):  
Michael O. Glocker ◽  
Kwabena F. M. Opuni ◽  
Hans-Juergen Thiesen
Keyword(s):  
Free Energy ◽  
Receptor Binding ◽  
Free Energy Calculations ◽  
Viral Fitness ◽  
Spike Protein ◽  
Receptor Protein ◽  
Binding Motif ◽  
Energy Calculations ◽  
Selection Processes ◽  
Protein Receptor

Our study focuses on free energy calculations of SARS-Cov2 spike protein receptor binding motives (RBMs) from wild type and variants-of-concern with particular emphasis on currently emerging SARS- CoV2 omicron variants of concern (VOC). Our computational free energy analysis underlines the occurrence of positive selection processes that specify omicron host adaption and bring changes on the molecular level into context with clinically relevant observations. Our free energy calculations studies regarding the interaction of omicron's RBM with human ACE2 shows weaker binding to ACE2 than alpha's, delta's, or wild type's RBM. Thus, less virus is predicted to be generated in time per infected cell. Our mutant analyses predict with focus on omicron variants a reduced spike-protein binding to ACE2--receptor protein possibly enhancing viral fitness / transmissibility and resulting in a delayed induction of danger signals as trade-off. Finally, more virus is produced but less per cell accompanied with delayed Covid-19 immunogenicity and pathogenicity. Regarding the latter, more virus is assumed to be required to initiate inflammatory immune responses.

scholarly journals BMP15 Suppresses Progesterone Production by Down-Regulating StAR via ALK3 in Human Granulosa Cells

2013 ◽  
Vol 27 (12) ◽  
pp. 2093-2104 ◽  
Author(s):  
Hsun-Ming Chang ◽  
Jung-Chien Cheng ◽  
Christian Klausen ◽  
Peter C. K. Leung
Keyword(s):  
Granulosa Cells ◽  
Critical Role ◽  
Regulatory Protein ◽  
Granulosa Cell Tumor ◽  
Type I ◽  
Mrna Levels ◽  
Protein Levels ◽  
Human Granulosa Cells ◽  
Progesterone Production ◽  
Steroidogenic Acute Regulatory

In addition to somatic cell-derived growth factors, oocyte-derived growth differentiation factor (GDF)9 and bone morphogenetic protein (BMP)15 play essential roles in female fertility. However, few studies have investigated their effects on human ovarian steroidogenesis, and fewer still have examined their differential effects or underlying molecular determinants. In the present study, we used immortalized human granulosa cells (SVOG) and human granulosa cell tumor cells (KGN) to compare the effects of GDF9 and BMP15 on steroidogenic enzyme expression and investigate potential mechanisms of action. In SVOG cells, neither GDF9 nor BMP15 affects the mRNA levels of P450 side-chain cleavage enzyme or 3β-hydroxysteroid dehydrogenase. However, treatment with BMP15, but not GDF9, significantly decreases steroidogenic acute regulatory protein (StAR) mRNA and protein levels as well as progesterone production. These suppressive effects, along with the induction of Sma and Mad-related protein (SMAD)1/5/8 phosphorylation, are attenuated by cotreatment with 2 different BMP type I receptor inhibitors (dorsomorphin and DMH-1). Furthermore, depletion of activin receptor-like kinase (ALK)3 using small interfering RNA reverses the effects of BMP15 on SMAD1/5/8 phosphorylation and StAR expression. Similarly, knockdown of ALK3 abolishes BMP15-induced SMAD1/5/8 phosphorylation in KGN cells. These results provide evidence that oocyte-derived BMP15 down-regulates StAR expression and decreases progesterone production in human granulosa cells, likely via ALK3-mediated SMAD1/5/8 signaling. Our findings suggest that oocyte may play a critical role in the regulation of progesterone to prevent premature luteinization during the late stage of follicle development.

scholarly journals The Global Regulatory Cyclic AMP Receptor Protein (CRP) Controls Multifactorial Fluoroquinolone Susceptibility in Salmonella enterica Serovar Typhimurium

2017 ◽  
Vol 61 (11) ◽  
Author(s):  
Stefani C. Kary ◽  
Joshua R. K. Yoneda ◽  
Stephen C. Olshefsky ◽  
Laura A. Stewart ◽  
Steven B. West ◽  
...  
Keyword(s):  
Cyclic Amp ◽  
Salmonella Enterica ◽  
Topoisomerase I ◽  
Multiple Drug Resistance ◽  
Regulatory Protein ◽  
Dna Supercoiling ◽  
Receptor Protein ◽  
Multiple Drug ◽  
Topoisomerase Iv ◽  
Fluoroquinolone Antibiotics

ABSTRACT Fluoroquinolone antibiotics are prescribed for the treatment of Salmonella enterica infections, but resistance to this family of antibiotics is growing. Here we report that loss of the global regulatory protein cyclic AMP (cAMP) receptor protein (CRP) or its allosteric effector, cAMP, reduces susceptibility to fluoroquinolones. A Δcrp mutation was synergistic with the primary fluoroquinolone resistance allele gyrA83, thus able to contribute to clinically relevant resistance. Decreased susceptibility to fluoroquinolones could be partly explained by decreased expression of the outer membrane porin genes ompA and ompF with a concomitant increase in the expression of the ciprofloxacin resistance efflux pump gene acrB in Δcrp cells. Expression of gyrAB, which encode the DNA supercoiling enzyme GyrAB, which is blocked by fluoroquinolones, and expression of topA, which encodes the dominant supercoiling-relaxing enzyme topoisomerase I, were unchanged in Δcrp cells. Yet Δcrp cells maintained a more relaxed state of DNA supercoiling, correlating with an observed increase in topoisomerase IV (parCE) expression. Surprisingly, the Δcrp mutation had the unanticipated effect of enhancing fitness in the presence of fluoroquinolone antibiotics, which can be explained by the observation that exposure of Δcrp cells to ciprofloxacin had the counterintuitive effect of restoring wild-type levels of DNA supercoiling. Consistent with this, Δcrp cells did not become elongated or induce the SOS response when challenged with ciprofloxacin. These findings implicate the combined action of multiple drug resistance mechanisms in Δcrp cells: reduced permeability and elevated efflux of fluoroquinolones coupled with a relaxed DNA supercoiling state that buffers cells against GyrAB inhibition by fluoroquinolones.

scholarly journals Enhanced expression of the complement regulatory protein, membrane inhibitor of reactive lysis (CD59), is regulated at the level of transcription

Blood ◽  
1993 ◽  
Vol 82 (3) ◽  
pp. 968-977
Author(s):  
MH Holguin ◽  
CB Martin ◽  
JH Weis ◽  
CJ Parker
Keyword(s):  
Protein Expression ◽  
Blot Analysis ◽  
Interleukin 1 ◽  
Critical Role ◽  
Regulatory Protein ◽  
Calcium Ionophore ◽  
Cytolytic Activity ◽  
Host Cells ◽  
Rna Expression ◽  
Enhanced Expression

The membrane inhibitor of reactive lysis (MIRL) is an 18-Kd glycosyl phosphatidylinositol anchored membrane glycoprotein that inhibits the cytolytic activity of complement. MIRL is expressed by all hematopoietic elements and by a wide variety of nonhematopoietic tissues. A deficiency of MIRL is primarily responsible for the greater sensitivity of the erythrocytes of paroxysmal nocturnal hemoglobinuria to complement mediated lysis. Because of its critical role in protecting host cells from injury by complement, we hypothesized that mechanisms exist that allow MIRL expression to be regulated. To investigate this hypothesis, both MIRL RNA and MIRL protein expression were analyzed following exposure of K562 erythroleukemia cells to a variety of potential stimulants. Incubation with dexamethasone, calcium ionophore, lipopolysaccharide, interleukin 1, tumor necrosis factor, hemin, and cyclic AMP had no effect on MIRL expression. However, incubation with phorbol 12-myristate 13 acetate (PMA), induced a marked increase in MIRL RNA as determined by Northern blot analysis. This enhanced expression of MIRL RNA was associated with an increase in MIRL protein expression as determined by immunoprecipitation of metabolically labeled proteins, Western blot analysis, and immunobinding assay. Enhanced MIRL RNA expression was first detected after 8 hours and increased through 24 hours of observation. Inhibitors of either protein synthesis or transcription abrogated the PMA-induced enhancement of MIRL RNA expression. Together, these results are consistent with a model in which PMA induces synthesis of a trans acting protein that enhances transcription of the MIRL gene.

IN SILICO CHARACTERIZATION AND MOLECULAR MODELLING OF SODIUM-DEPENDENT SEROTONIN TRANSPORTER PROTEIN FROM HOMO SAPIENS

2017 ◽  
Vol 10 (8) ◽  
pp. 299
Author(s):  
Hina Bansal ◽  
Neetu Jabalia
Keyword(s):  
Homology Modeling ◽  
Serotonin Transporter ◽  
In Silico ◽  
Tertiary Structure ◽  
Homo Sapiens ◽  
Receptor Protein ◽  
Sudden Infant ◽  
Protein Disorder ◽  
Computational Tools ◽  
Sodium Dependent

Objective: The objective of our investigation is to apply computational tools for a protein sodium-dependent serotonin transporter (SERT). It plays a role in sudden infant death syndrome, aggressive behavior in Alzheimer disease, and depression-susceptibility. Although various conventional and experimental therapies have been directed for the treatment, still it needs attention for more effective treatments. Toward this pursuit, we performed in silico analysis of the protein using computational tools and servers.Methods: Homology modeling approach has been used to define the tertiary structure of the protein using SWISS-MODEL workspace. Modal validation was done to verify the generated modal. Furthermore, primary and secondary structural and functional analysis was performed to provide more perceptions into the selected protein. The protein disorder analysis was performed using PrDOS server.Results: The results of the primary structure analyses suggested that SERT is an acidic and hydrophobic protein in nature. It is structurally stable. The secondary structural analysis results revealed that random coils dominated among secondary structure elements. The homology modeling showed that the QMEAN score of the model was −5.17, and the sequence identity was 52%. Validation protein models using Rampage revealed that more that 95.9% residues were in favored regions. The protein disorder detected by PrDOS showed the total disorder amino acid residues were 89 (14.1%).Conclusion: The study provides valuable clues for initiation of experimental characterization of this protein and throws light on some novel insights into the structural features of sodium-dependent SERT protein from Homo sapiens. This will also helpful in conducting docking studies for the receptor protein against various drug molecules. 

scholarly journals Regulation of intracellular membrane trafficking and cell dynamics by syntaxin-6

2012 ◽  
Vol 32 (4) ◽  
pp. 383-391 ◽  
Author(s):  
Jae-Joon Jung ◽  
Shivangi M. Inamdar ◽  
Ajit Tiwari ◽  
Amit Choudhury
Keyword(s):  
Membrane Trafficking ◽  
Critical Role ◽  
Cell Types ◽  
Intracellular Membrane ◽  
Cellular Functions ◽  
Cell Dynamics ◽  
Transport Pathways ◽  
Protein Receptor ◽  
Secretory Transport ◽  
Target Membrane

Intracellular membrane trafficking along endocytic and secretory transport pathways plays a critical role in diverse cellular functions including both developmental and pathological processes. Briefly, proteins and lipids destined for transport to distinct locations are collectively assembled into vesicles and delivered to their target site by vesicular fusion. SNARE (soluble N-ethylmaleimide-sensitive factor-attachment protein receptor) proteins are required for these events, during which v-SNAREs (vesicle SNAREs) interact with t-SNAREs (target SNAREs) to allow transfer of cargo from donor vesicle to target membrane. Recently, the t-SNARE family member, syntaxin-6, has been shown to play an important role in the transport of proteins that are key to diverse cellular dynamic processes. In this paper, we briefly discuss the specific role of SNAREs in various mammalian cell types and comprehensively review the various roles of the Golgi- and endosome-localized t-SNARE, syntaxin-6, in membrane trafficking during physiological as well as pathological conditions.

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