Search results for "cytoglobin"
showing 10 items of 38 documents
New insight into the haemoglobin superfamily: preliminary crystallographic characterization of human cytoglobin.
2003
Human cytoglobin, present in almost all tissue types, is a newly identified member of the Hb superfamily. A double mutant, having both cysteines replaced by serines, has been overexpressed in Escherichia coli, purified and crystallized. A highly redundant SAD data set has been collected at the haem Fe-atom absorption edge (lambda = 1.720 A) to 2.60 A resolution. The crystals belong to the orthorhombic P2(1)2(1)2(1) space group, with unit-cell parameters a = 46.8, b = 73.1, c = 98.9 A and two molecules per asymmetric unit. The anomalous difference Patterson map clearly reveals the position of the haem Fe-atom sites, thus paving the way for SAD structure determination.
Divergent distribution of cytoglobin and neuroglobin in the murine eye
2005
Neuroglobin (Ngb) and cytoglobin (Cygb) are two vertebrate globins with yet poorly defined functions. Previous studies had demonstrated a high expression level of neuroglobin in the mammalian retina, being in line with a respiratory function. Here we show that in the mouse eye, cytoglobin is localised in fibroblasts of the ciliary processes and the choroidea. In the neuronal retina, cytoglobin is expressed in a subset of neurons of the ganglion cell and inner nuclear layers. Cytoglobin is also present in the inner plexiform layer, but absent from the pigment cells. Neuroglobin is localised in photoreceptor inner segments, the plexiform layers and the ganglion cell layer. The divergent distr…
Neuroglobin and cytoglobin overexpression protects human SH-SY5Y neuroblastoma cells against oxidative stress-induced cell death
2006
Although reactive oxygen species (ROS) at physiological concentrations are required for normal cell function, excessive production of ROS is detrimental to cells. Neuroglobin and cytoglobin are two globins, whose functions are still a matter of debate. A potential role in the detoxification of ROS is suggested. The influence of neuroglobin and cytoglobin on cell death after oxidative stress in human neuroblastoma SH-SY5Y cells was evaluated. Exposure of SH-SY5Y cells to paraquat or H(2)O(2) resulted in a concentration- and time-dependent induction of apoptotic and necrotic cell death. H(2)O(2) was 16 times more potent to induce cell death as compared to paraquat. SH-SY5Y cells transfected w…
Old proteins - new locations: myoglobin, haemoglobin, neuroglobin and cytoglobin in solid tumours and cancer cells
2010
Aim: The unexpected identification of myoglobin (MB) in breast cancer prompted us to evaluate the clinico-pathological value of MB, haemoglobin (HB) and cytoglobin (CYGB) in human breast carcinoma cases. We further screened for the presence of neuroglobin (NGB) and CYGB in tumours of diverse origin, and assessed the O2-response of HB, MB and CYGB mRNAs in cancer cell lines, to better elicit the links between this ectopic globin expression and tumour hypoxia. Methods: Breast tumours were analysed by immunohistochemistry for HB, MB and CYGB and correlated with clinico-pathological parameters. Screening for CYGB and NGB mRNA expression in tumour entities was performed by hybridization, quant…
Hypoxia induces a complex response of globin expression in zebrafish (Danio rerio).
2006
SUMMARY Unlike most mammals, many fish species live and survive in environments with low or changing levels of oxygen. Respiratory proteins like hemoglobin or myoglobin bind or store oxygen, thus enhancing its availability to the respiratory chain in the mitochondria. Here we investigate by means of quantitative real-time PCR the changes of hemoglobin, myoglobin, neuroglobin,cytoglobin and globin X mRNA in zebrafish (Danio rerio) exposed to mild (PO2=∼8.6 kPa) or severe(PO2=∼4.1 kPa) hypoxia. Neuroglobin and myoglobin protein levels were investigated by western blotting. Whereas mild hypoxia caused only minor changes of mRNA levels, strong hypoxia enhanced mRNA levels of the control genes (…
What is the function of neuroglobin?
2009
SUMMARY For a long time, haemoglobin and myoglobin had been assumed to represent the only globin types of vertebrates. In 2000, however, we discovered a third globin type by mining the genome sequence data. Based on a preferential expression in the nervous system, this globin is referred to as neuroglobin. Despite nine years of research, its function is still uncertain and a number of hypotheses have been put forward. Neuroglobin enhances cell viability under hypoxia and under various types of oxidative stress in transgenic systems, but does not appear to be strongly upregulated in response to stress. A close phylogenetic relationship with invertebrate nerve globins and its positive correla…
Human Brain Neuroglobin Structure Reveals a Distinct Mode of Controlling Oxygen Affinity
2003
Neuroglobin, mainly expressed in vertebrate brain and retina, is a recently identified member of the globin superfamily. Augmenting O(2) supply, neuroglobin promotes survival of neurons upon hypoxic injury, potentially limiting brain damage. In the absence of exogenous ligands, neuroglobin displays a hexacoordinated heme. O(2) and CO bind to the heme iron, displacing the endogenous HisE7 heme distal ligand. Hexacoordinated human neuroglobin displays a classical globin fold adapted to host the reversible bis-histidyl heme complex and an elongated protein matrix cavity, held to facilitate O(2) diffusion to the heme. The neuroglobin structure suggests that the classical globin fold is endowed …
A vertebrate globin expressed in the brain.
2000
Haemoglobins and myoglobins constitute related protein families that function in oxygen transport and storage in humans and other vertebrates. Here we report the identification of a third globin type in man and mouse. This protein is predominantly expressed in the brain, and therefore we have called it neuroglobin. Mouse neuroglobin is a monomer with a high oxygen affinity (half saturation pressure, P50 approximately 2 torr). Analogous to myoglobin, neuroglobin may increase the availability of oxygen to brain tissue. The human neuroglobin gene (NGB), located on chromosome 14q24, has a unique exon-intron structure. Neuroglobin represents a distinct protein family that diverged early in metaz…
The Globin Gene Repertoire of Lampreys: Convergent Evolution of Hemoglobin and Myoglobin in Jawed and Jawless Vertebrates
2014
Agnathans (jawless vertebrates) occupy a key phylogenetic position for illuminating the evolution of vertebrate anatomy and physiology. Evaluation of the agnathan globin gene repertoire can thus aid efforts to reconstruct the origin and evolution of the globin genes of vertebrates, a superfamily that includes the well-known model proteins hemoglobin and myoglobin. Here, we report a comprehensive analysis of the genome of the sea lamprey (Petromyzon marinus )w hich revealed 23 intact globin genes and two hemoglobin pseudogenes. Analyses of the genome of the Arctic lamprey (Lethenteron camtschaticum) identified 18 full length and five partial globin gene sequences. The majority of the globin …
Neuroglobin, cytoglobin, and myoglobin contribute to hypoxia adaptation of the subterranean mole rat Spalax.
2010
The subterranean mole rat Spalax is an excellent model for studying adaptation of a mammal toward chronic environmental hypoxia. Neuroglobin (Ngb) and cytoglobin (Cygb) are O 2 -binding respiratory proteins and thus candidates for being involved in molecular hypoxia adaptations of Spalax . Ngb is expressed primarily in vertebrate nerves, whereas Cygb is found in extracellular matrix-producing cells and in some neurons. The physiological functions of both proteins are not fully understood but discussed with regard to O 2 supply, the detoxification of reactive oxygen or nitrogen species, and apoptosis protection. Spalax Ngb and Cygb coding sequences are strongly conserved. However, mRNA and …