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Stephen S Tobe - One of the best experts on this subject based on the ideXlab platform.
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hemolymph proteomics and gut microbiota of horseshoe crabs tachypleus tridentatus and carcinoscorpius rotundicauda
Frontiers in Marine Science, 2020Co-Authors: Thomas C N Leung, William G Bendena, Stephen S Tobe, Wenyan Nong, Ho Yin Yip, Ivy H T Lee, S G Cheung, Ngai Sai Ming, Jerome H L HuiAbstract:Horseshoe crabs are a group of marine chelicerates that contain only four extant species, and some of which become endangered. Their hemolymph has been widely used in medical applications for endotoxins detection. Nevertheless, there are only limited information on the profiles of their hemolymph Proteins and gut microbiota diversity. In this study, we performed the first detailed investigation of the hemolymph proteomics and gut microbiota of two Asian horseshoe crabs Tachypleus tridentatus and Carcinoscorpius rotundicauda. Among the identified Proteins being catalogued in the juvenile and adult hemolymph, unexpectedly, sesquiterpenoids signaling pathway Proteins including Heat shock Protein 83 (HSP83), Chd64 and a juvenile Hormone Binding Protein (JHBP) were revealed. This provides evidence for the presence of functional sesquiterpenoid hormonal systems in these marine chelicerates. Consumption of horseshoe crabs often leads to tetrodotoxin poisoning and the horseshoe crab is thought to possess a tetrodoxin resistance mechanism. As such, sodium channels were analysed and found to have critical amino acid residues that are similar to the toxin resistant pufferfish sodium channels. The source of the toxin is unknown so we investigated the gut microbiota, and found that Clostridium and Vibrio were the most dominant bacteria in T. tridentatus and C. rotundicauda, respectively. Together, this study provides a framework for further understanding of sesquiterpenoids and gut microbiota of these marine chelicerates.
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identification of putative ecdysteroid and juvenile Hormone pathway genes in the shrimp neocaridina denticulata
General and Comparative Endocrinology, 2015Co-Authors: Yung Wa Sin, Ka Wo Chan, Nathan J Kenny, Sam P S Cheong, Ricky Wai Tak Leung, Tingfung Chan, William G Bendena, Ka Hou Chu, Stephen S TobeAbstract:Although the sesquiterpenoid juvenile Hormone (JH) and the steroidal ecdysteroids are of vital importance to the development and reproduction of insects, our understanding of the evolution of these crucial hormonal regulators in other arthropods is limited. To better understand arthropod Hormone evolution and regulation, here we describe the hormonal pathway genes (e.g. those involved in Hormone biosynthesis, degradation, regulation and signal transduction) of a new decapod model, the shrimp Neocaridina denticulata. The majority of known insect sesquiterpenoid and ecdysteroid pathway genes and their regulators are contained in the N. denticulata genome. In the sesquiterpenoid pathway, these include biosynthetic pathway components: juvenile Hormone acid methyltransferase (JHAMT); Hormone Binding Protein: juvenile Hormone Binding Protein (JHBP); and degradation pathway components: juvenile Hormone esterase (JHE), juvenile Hormone esterase Binding Protein (JHEBP) and juvenile Hormone epoxide hydrolase (JHEH), with the JHBP, JHEBP and JHEH genes being discovered in a crustacean for the first time here. Ecdysteroid biosynthetic pathway genes identified include spook, phantom, disembodied, shadow and CYP18. Potential hormonal regulators and signal transducers such as allatostatins (ASTs), Methoprene-tolerant (Met), Retinoid X receptor (RXR), Ecdysone receptor (EcR), calponin-like Protein Chd64, FK509-Binding Protein (FKBP39), Broad-complex (Br-c), and crustacean hyperglycemic Hormone/molt-inhibiting Hormone/gonad-inhibiting Hormone (CHH/MIH/GIH) genes are all present in the shrimp N. denticulata. To our knowledge, this is the first report of these hormonal pathways and their regulatory genes together in a single decapod, providing a vital resource for further research into development, reproduction, endocrinology and evolution of crustaceans, and arthropods in general.
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cytosolic and nuclear juvenile Hormone Binding Proteins from the brain of diploptera punctata
General and Comparative Endocrinology, 1994Co-Authors: L E King, Jinrui Zhang, Stephen S TobeAbstract:Cytosol and crude nuclear extracts of brains from female Diploptera punctata were found to contain a juvenile Hormone-Binding Protein. The Binding kinetics of the cytosol and nuclear juvenile Hormone-Binding Proteins toward racemic [3H]JH III were determined using the dextran-coated charcoal assay. Both Proteins show reversible and saturable Binding toward JH III. The mean dissociation constant (Kd) of the brain cytosol Binding Protein was 66.5 +/- 7.2 nM, whereas the nuclear-Binding Protein had a lower affinity, with a mean Kd of 170 +/- 22.1 nM. The specificity of both the cytosol and the nuclear Binding Proteins was determined by competitive displacement experiments with [3H]JH III. For the cytosol Binding Protein, the order of relative affinity was JH II > (10R)-JH III > (10RS)-JH III approximately JH I. For the nuclear Binding Protein the order of relative affinity was JH II > JH I > (10R)-JH III > (10RS)-JH III. The JH analog hydroprene (ZR 512) had > 100-fold lower affinity than JH III for both Proteins.
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the structure of a juvenile Hormone Binding lipophorin from the hemolymph of diploptera punctata
Insect Biochemistry and Molecular Biology, 1992Co-Authors: L E King, Stephen S TobeAbstract:Abstract The high molecular weight, high affinity juvenile Hormone Binding Protein from the hemolymph of Diploptera punctata was identified as a lipophorin by gradient KBr ultracentrifugation and SDS gradient PAGE. This juvenile Hormone Binding lipophorin (JHBL) was composed of two subunits, apolipoProtein I (230 kDa mol. wt) and apolipoProtein II (80 kDa mol. wt). The density of the native Protein was 1.15 g/ml. Photoaffinity labeling using the JH analog [ 3 H]EFDA demonstrated that the JH Binding site resides on apolipoProtein I. The amino acid composition of both native lipophorin and its two subunits was determined and the N-terminal sequence of the 80 kDa apolipoProtein described for 19 of the first 21 amino acids. This sequence did not have similarity to any known Protein. The N-terminus of the 230 kDa apolipoProtein was blocked. The specificity of a monoclonal antibody to purified native JHBL was also demonstrated. We show that the monoclonal antibody was specific to the 230 kDa subunit and did not recognize the 80 kDa apolipoProtein.
Audrey F. Seasholtz - One of the best experts on this subject based on the ideXlab platform.
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cell type specific expression of corticotropin releasing Hormone Binding Protein in gabaergic interneurons in the prefrontal cortex
Frontiers in Neuroanatomy, 2017Co-Authors: Audrey F. Seasholtz, Kyle D Ketchesin, Nicholas S HuangAbstract:Corticotropin-releasing Hormone-Binding Protein (CRH-BP) is a secreted glycoProtein that binds CRH with very high affinity to modulate CRH receptor activity. CRH-BP is widely expressed throughout the brain, with particularly high expression in regions such as the amygdala, hippocampus, ventral tegmental area and prefrontal cortex (PFC). Recent studies suggest a role for CRH-BP in stress-related psychiatric disorders and addiction, with the PFC being a potential site of interest. However, the molecular phenotype of CRH-BP-expressing cells in this region has not been well-characterized. In the current study, we sought to determine the cell type-specific expression of CRH-BP in the PFC to begin to define the neural circuits in which this key regulator is acting. To characterize the expression of CRH-BP in excitatory and/or inhibitory neurons, we utilized dual in situ hybridization to examine the cellular colocalization of CRH-BP mRNA with vesicular glutamate transporter (VGLUT) or glutamic acid decarboxylase (GAD) mRNA in different subregions of the PFC. We show that CRH-BP is expressed predominantly in GABAergic interneurons of the PFC, as revealed by the high degree of colocalization (>85%) between CRH-BP and GAD. To further characterize the expression of CRH-BP in this heterogenous group of inhibitory neurons, we examined the colocalization of CRH-BP with various molecular markers of GABAergic interneurons, including parvalbumin (PV), somatostatin (SST), vasoactive intestinal peptide (VIP) and cholecystokinin (CCK). We demonstrate that CRH-BP is colocalized predominantly with SST in the PFC, with lower levels of colocalization in PV- and CCK-expressing neurons. Our results provide a more comprehensive characterization of the cell type-specific expression of CRH-BP and begin to define its potential role within circuits of the PFC. These results will serve as the basis for future in vivo studies to manipulate CRH-BP in a cell type-specific manner to better understand its role in stress-related psychiatric disorders, including anxiety, depression and addiction.
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corticotropin releasing Hormone Binding Protein and stress from invertebrates to humans
Stress, 2017Co-Authors: Kyle D Ketchesin, Gwen S Stinnett, Audrey F. SeasholtzAbstract:Corticotropin-releasing Hormone (CRH) is a key regulator of the stress response. This peptide controls the hypothalamic-pituitary-adrenal (HPA) axis as well as a variety of behavioral and autonomic stress responses via the two CRH receptors, CRH-R1 and CRH-R2. The CRH system also includes an evolutionarily conserved CRH-Binding Protein (CRH-BP), a secreted glycoProtein that binds CRH with subnanomolar affinity to modulate CRH receptor activity. In this review, we discuss the current literature on CRH-BP and stress across multiple species, from insects to humans. We describe the regulation of CRH-BP in response to stress, as well as genetic mouse models that have been utilized to elucidate the in vivo role(s) of CRH-BP in modulating the stress response. Finally, the role of CRH-BP in the human stress response is examined, including single nucleotide polymorphisms in the human CRHBP gene that are associated with stress-related affective disorders and addiction. Lay summary The stress response is controlled by corticotropin-releasing Hormone (CRH), acting via CRH receptors. However, the CRH system also includes a unique CRH-Binding Protein (CRH-BP) that binds CRH with an affinity greater than the CRH receptors. In this review, we discuss the role of this highly conserved CRH-BP in regulation of the CRH-mediated stress response from invertebrates to humans.
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estrogen receptor er mediated transcriptional regulation of the human corticotropin releasing Hormone Binding Protein promoter differential effects of erα and erβ
Molecular Endocrinology, 2004Co-Authors: Anja Van De Stolpe, Audrey F. Seasholtz, Annika J Slycke, Marjolein O Reinders, Anna W M Zomer, Sharon Goodenough, Christian Behl, Paul T Van Der SaagAbstract:CRH-Binding Protein (CRH-BP) regulates activation of the hypothalamic-pituitary-adrenal (HPA) axis by Binding and inhibiting CRH. We investigated for the first time transcriptional regulation of the human CRH-BP promoter using transient transfections. Estrogen receptors (ERs) contributed to ligand-independent constitutive activation of the promoter, whereas in the presence of estradiol ERα induced and ERβ repressed promoter activity in a dose-dependent manner. TNFα inhibited promoter induction by ERα in the absence and presence of estradiol. Three ERE half-sites in the CRH-BP promoter bound ERα and ERβ in an EMSA, and disruption of ERE half-sites by site-directed mutagenesis abolished ligand-independent induction by ERα and ERβ and promoter enhancement by estradiol-activated ERα. Repression by estradiol/ERβ was unaffected by disruption of ERE half-sites, activating Protein 1, cAMP response element, GATA, or nuclear factor κB sites, and reversed to promoter induction by estrogen antagonists, tamoxifen and ...
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corticotropin releasing Hormone Binding Protein biochemistry and function from fishes to mammals
Journal of Endocrinology, 2002Co-Authors: Audrey F. Seasholtz, Roldan A Valverde, Robert J DenverAbstract:Corticotropin-releasing Hormone (CRH) plays multiple roles in vertebrate species. In mammals, it is the major hypothalamic releasing factor for pituitary adrenocorticotropin secretion, and is a neurotransmitter or neuromodulator at other sites in the central nervous system. In non-mammalian vertebrates, CRH not only acts as a neurotransmitter and hypophysiotropin, it also acts as a potent thyrotropin-releasing factor, allowing CRH to regulate both the adrenal and thyroid axes, especially in development. The recent discovery of a family of CRH-like peptides suggests that multiple CRH-like ligands may play important roles in these functions. The biological effects of CRH and the other CRH-like ligands are mediated and modulated not only by CRH receptors, but also via a highly conserved CRH-Binding Protein (CRH-BP). The CRH-BP has been identified not only in mammals, but also in non-mammalian vertebrates including fishes, amphibians, and birds, suggesting that it is a phylogenetically ancient Protein with extensive structural and functional conservation. In this review, we discuss the biochemical properties of the characterized CRH-BPs and the functional roles of the CRH-BP. While much of the in vitro and in vivo data to date support an 'inhibitory' role for the CRH-BP in which it binds CRH and other CRH-like ligands and prevents the activation of CRH receptors, the possibility that the CRH-BP may also exhibit diverse extra- and intracellular roles in a cell-specific fashion and at specific times in development is also discussed.
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altered anxiety and weight gain in corticotropin releasing Hormone Binding Protein deficient mice
Proceedings of the National Academy of Sciences of the United States of America, 1999Co-Authors: I J Karolyi, Heather L Burrows, Tennore Ramesh, M Nakajima, J S Lesh, Eunju Seong, Sally A Camper, Audrey F. SeasholtzAbstract:Corticotropin-releasing Hormone (CRH) is widely recognized as the primary mediator of the neuroendocrine and behavioral responses to stress, including stress-induced anxiety. The biological activity of CRH and other mammalian CRH-like peptides, such as urocortin, may be modulated by CRH-Binding Protein (CRH-BP). To assess directly the CRH-BP function, we created a mouse model of CRH-BP deficiency by gene targeting. Basal adrenocorticotropic Hormone and corticosterone levels are unchanged in the CRH-BP-deficient mice, and the animals demonstrate a normal increase in adrenocorticotropic Hormone and corticosterone after restraint stress. In contrast, adult male CRH-BP-deficient mice show significantly reduced body weight when compared with wild-type controls. CRH-BP-deficient mice also exhibit a significant increase in anxiogenic-like behavior as assessed by the elevated plus maze and defensive withdrawal tests. The increased anorectic and anxiogenic-like behavior most likely is caused by increased “free” CRH and/or urocortin levels in the brain of CRH-BP-deficient animals, suggesting an important role for CRH-BP in maintaining appropriate levels of these peptides in the central nervous system.
Coby Schal - One of the best experts on this subject based on the ideXlab platform.
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lipophorin of female blattella germanica l characterization and relation to hemolymph titers of juvenile Hormone and hydrocarbons
Journal of Insect Physiology, 1999Co-Authors: Veeresh Sevala, Shengqiang Shu, Sonny B Ramaswamy, Coby SchalAbstract:Abstract High density lipophorin (HDLp) from the hemolymph of the German cockroach, Blattella germanica (L.) (Family Blattellidae), has an apparent molecular weight of 670 kDa, with an isoelectric point of 7.0 and a density of 1.109 g/ml. It is composed of two subunits, apolipoProtein-I (212 kDa) and apolipoProtein-II (80 kDa), and consists of 51.4% lipid, 46.2% Protein and 2.4% carbohydrate. Hydrocarbons constitute 42.2% of the total lipids which also contain diacylglycerol, cholesterol and phospholipid. Lipophorin is rich in the amino acids glutamic acid, aspartic acid, lysine, valine, and leucine. Specificity of a polyclonal antibody was demonstrated by Western blotting and Ouchterlony immunodiffusion: the antiserum recognized native HDLp and apolipoProtein-I, but not apolipoProtein-II, purified vitellin, or other hemolymph Proteins. It also recognized a Protein in the hemolymph of Supella longipalpa (Blattellidae) but did not cross-react with hemolymph Proteins from Periplaneta americana (Blattidae) or Diploptera punctata (Blaberidae). An enzyme-linked immunosorbent assay was developed to measure the HDLp titer in the hemolymph of adult females. The titer of HDLp, a juvenile Hormone Binding Protein, exhibited no clear relationship to the changing titer of juvenile Hormone in hemolymph. The hemolymph titer of hydrocarbon, which is also carried by HDLp, showed some functional relation to the concentration of HDLp in the hemolymph. Because it concurrently serves multiple functions in insect development and reproduction, lipophorin titer might covary with the titers of lipid ligands that occur at high concentrations and require extensive shuttling through the hemolymph.
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sites of synthesis and transport pathways of insect hydrocarbons cuticle and ovary as target tissues
Integrative and Comparative Biology, 1998Co-Authors: Coby Schal, Veeresh Sevala, Hugh P Young, Jane A S BachmannAbstract:SYNOPSIS. The outer surface of insects is covered with a lipid layer that provides water-proofing and protection against environmental stresses. Hydrocarbons (HC) are major constituents of this epicuticular wax and they also serve as semiochemicals. In some insects HC are also exploited as biosynthetic precursors for pheromones. HC are synthesized by oenocytes which are situated in the integument or hemocoel. Shuttling of HC to the epicuticle, fat body, and gonads requires transport through an aqueous medium. Insects, unlike vertebrates, use a versatile lipoProtein to effect lipid transport and to selectively deliver lipids to specific tissues. A high-density hemolymph lipoProtein (lipophorin [Lp]) serves this function. In adult females of the German cockroach (Blattella germanica), Lp carries both HC and a contact sex pheromone. Lipophorin is a multi-functional lipid carrier serving also as a juvenile Hormone Binding Protein in many insects. Studies of the interactions between Lp and HC are beginning to unravel the routes used in delivering HC to target tissues. We discuss the pathways and dynamics of loading of Lp with HC and HC-derived pheromones, their transport through the hemolymph, and deposition in various tissues, including the epicuticle, ovaries, and pheromone-emitting glands.
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lipophorin a hemolymph juvenile Hormone Binding Protein in the german cockroach blattella germanica
Insect Biochemistry and Molecular Biology, 1997Co-Authors: Veeresh Sevala, Jane A S Bachmann, Coby SchalAbstract:Abstract We examined the Binding of [ 3 H](10 R ) juvenile Hormone (JH) III to lipophorin that was purified from the hemolymph of Blattella germanica . Binding was found to be specific, saturable and with high affinity to JH III. Using Scatchard analysis, the equilibrium dissociation constant (K d ) and total Binding capacity (B max ) were estimated to be 9.75±0.64 nM and 0.241±0.02 nmol/mg Protein, respectively. Competitive displacement studies with racemic JH III, JH I, cuticular hydrocarbon, contact sex pheromone, and the JH analogs pyriproxyfen, fenoxycarb, and hydroprene showed that only JH III readily displaced [ 3 H](10 R )JH III from the Binding site. However, hydroprene competed for the JH III Binding site more effectively than the other two JH analogs. Photoaffinity labelling using the JH III analog [ 3 H]epoxyfarnesyl diazoacetate demonstrated that the JH Binding site was on apolipophorin-I, the large subunit of the lipophorin complex.
Kerry Richard - One of the best experts on this subject based on the ideXlab platform.
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secretion and transfer of the thyroid Hormone Binding Protein transthyretin by human placenta
Placenta, 2012Co-Authors: R H Mortimer, Kelly Landers, Biju Balakrishnan, Murray D Mitchell, Jatin Patel, Kerry RichardAbstract:Abstract Context The thyroid Hormone and retinol Binding Protein transthyretin (TTR) is synthesised by human trophoblasts. Polarised JEG-3 choriocarcinoma cells grown in bicameral chambers secrete TTR predominantly apically but also basally and these cells and human trophoblasts also take up TTR suggesting that there may be a placental TTR shuttle that participates in materno-fetal transfer of thyroid Hormones and retinol. Objectives and methods Our objective was to investigate TTR secretion into the maternal and fetal circuits of the ex vivo dually perfused placental lobule to confirm that placenta secretes TTR into the fetal circulation. We also investigated translocation of Alexa Fluor-594 labelled TTR from incubation medium into the fetal placental capillaries in early (14–15 weeks) and term placental villus explants. Results The perfused placental lobule secretes TTR into the maternal and fetal circuits. Secretion in both circuits is linear with time and is predominantly into the maternal circuit (mean maternal/fetal ratio 99.4 ± 25.6). The mean data fitted well to a three compartment mathematical model (maternal circuit, placenta and fetal circuit, constant secretion of TTR and return of maternal circuit TTR to the placental compartment). Explants from early (14–15 weeks) and late (38–40 weeks) placentas translocated fluorescently labelled TTR from medium to villus (fetal) capillaries. Conclusions Our results confirm that human placenta secretes TTR into maternal and fetal circulations and supports the hypothesis that placental TTR secreted into the maternal placental circulation can be taken up by trophoblasts and translocated to the fetal circulation, forming a TTR shuttle system. This may have important implications for materno-fetal transfer of thyroid Hormones, retinol/retinol Binding Protein and xenobiotics (such as polychlorinated biphenyls) all of which bind to TTR.
Kyle D Ketchesin - One of the best experts on this subject based on the ideXlab platform.
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cell type specific expression of corticotropin releasing Hormone Binding Protein in gabaergic interneurons in the prefrontal cortex
Frontiers in Neuroanatomy, 2017Co-Authors: Audrey F. Seasholtz, Kyle D Ketchesin, Nicholas S HuangAbstract:Corticotropin-releasing Hormone-Binding Protein (CRH-BP) is a secreted glycoProtein that binds CRH with very high affinity to modulate CRH receptor activity. CRH-BP is widely expressed throughout the brain, with particularly high expression in regions such as the amygdala, hippocampus, ventral tegmental area and prefrontal cortex (PFC). Recent studies suggest a role for CRH-BP in stress-related psychiatric disorders and addiction, with the PFC being a potential site of interest. However, the molecular phenotype of CRH-BP-expressing cells in this region has not been well-characterized. In the current study, we sought to determine the cell type-specific expression of CRH-BP in the PFC to begin to define the neural circuits in which this key regulator is acting. To characterize the expression of CRH-BP in excitatory and/or inhibitory neurons, we utilized dual in situ hybridization to examine the cellular colocalization of CRH-BP mRNA with vesicular glutamate transporter (VGLUT) or glutamic acid decarboxylase (GAD) mRNA in different subregions of the PFC. We show that CRH-BP is expressed predominantly in GABAergic interneurons of the PFC, as revealed by the high degree of colocalization (>85%) between CRH-BP and GAD. To further characterize the expression of CRH-BP in this heterogenous group of inhibitory neurons, we examined the colocalization of CRH-BP with various molecular markers of GABAergic interneurons, including parvalbumin (PV), somatostatin (SST), vasoactive intestinal peptide (VIP) and cholecystokinin (CCK). We demonstrate that CRH-BP is colocalized predominantly with SST in the PFC, with lower levels of colocalization in PV- and CCK-expressing neurons. Our results provide a more comprehensive characterization of the cell type-specific expression of CRH-BP and begin to define its potential role within circuits of the PFC. These results will serve as the basis for future in vivo studies to manipulate CRH-BP in a cell type-specific manner to better understand its role in stress-related psychiatric disorders, including anxiety, depression and addiction.
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corticotropin releasing Hormone Binding Protein and stress from invertebrates to humans
Stress, 2017Co-Authors: Kyle D Ketchesin, Gwen S Stinnett, Audrey F. SeasholtzAbstract:Corticotropin-releasing Hormone (CRH) is a key regulator of the stress response. This peptide controls the hypothalamic-pituitary-adrenal (HPA) axis as well as a variety of behavioral and autonomic stress responses via the two CRH receptors, CRH-R1 and CRH-R2. The CRH system also includes an evolutionarily conserved CRH-Binding Protein (CRH-BP), a secreted glycoProtein that binds CRH with subnanomolar affinity to modulate CRH receptor activity. In this review, we discuss the current literature on CRH-BP and stress across multiple species, from insects to humans. We describe the regulation of CRH-BP in response to stress, as well as genetic mouse models that have been utilized to elucidate the in vivo role(s) of CRH-BP in modulating the stress response. Finally, the role of CRH-BP in the human stress response is examined, including single nucleotide polymorphisms in the human CRHBP gene that are associated with stress-related affective disorders and addiction. Lay summary The stress response is controlled by corticotropin-releasing Hormone (CRH), acting via CRH receptors. However, the CRH system also includes a unique CRH-Binding Protein (CRH-BP) that binds CRH with an affinity greater than the CRH receptors. In this review, we discuss the role of this highly conserved CRH-BP in regulation of the CRH-mediated stress response from invertebrates to humans.