Besides it's role as a glycolytic enzyme, mammalian GPI can function as a tumor-secreted cytokine and an angiogenic factor (AMF) that stimulates endothelial cell motility. GPI is also a neurotrophic factor (Neuroleukin) for spinal and sensory neurons.
Autocrine motility factor (AMF) is a type of tumor-secreted cytokine which primarily stimulates tumor cell motility via receptor-mediated signaling pathways, and is thought to be connected to tumor progression and metastasis. Using in vivo models, we showed that critical neovascularization responded to a biological amount of AMF. This angiogenic activity was fixed by specific inhibitors against AMF. AMF stimulated in vitro motility of human umbilical vein endothelial cells (HUVECs), inducing the expression of cell surface AMF receptor localizing a single predominant perinuclear pattern closely correlated with its motile ability. AMF also elicited the formation of tube-like structures mimicking angiogenesis when HUVECs were grown in three-dimensional type I collagen gels. We further immunohistochemically detected AMF receptors on the surrounding sites of newborn microvessels. These findings suggest that AMF is a possible tumor progressive angiogenic factor which may act in a paracrine manner for the endothelial cells in the clinical neoplasm, and it will be a new target for antiangiogenic treatment.
Phosphohexose isomerase (PHI) is a member of the ectoenzyme/exoenzyme family and plays a key role in both glycolysis and gluconeogenesis pathways. Upon secretion PHI acts as a cytokine with tumor autocrine motility factor (AMF), neuroleukin (NLK) and maturation factor (MF) functions. Signaling is initiated by its binding to a cell surface 78 kDa glycoprotein (gp78). However, since PHI protein is a 'leaderless' secretory protein, released from cells via a non-classical route(s), we questioned whether the molecule undergoes post-translation modification while retaining proper folding and maintaining intact enzymatic and motogenic activities. To address this, we have generated, expressed and isolated a recombinant human AMF (rhAMF). The rhAMF retained the biological activities of the native AMF, i.e., catalyzes phosphohexose isomerization and stimulated cell motility. Additionally, we show here that human PHI is phosphorylated at serine 185 by casein kinase II (CK II) and we provide experimental evidence suggesting that this phosphorylation is associated with secretion, thus providing insights for elucidating the intracellular signal transmission of cell response to stimulation by AMF/NLK/MF.
Phosphoglucose isomerase (PGI) is a cytosolic glycolytic enzyme that also functions as an extracellular cytokine (neuroleukin/autocrine motility factor (AMF)/maturation factor). Contrary to mammalian PGI, bacterial PGI was not internalized by the PGI/AMF receptor (gp78/AMF-R) and neither bacterial nor yeast PGI competed with mammalian PGI for receptor binding and internalization. Furthermore, while the bacterial, yeast and mammalian preparations all exhibited isomerase activity, only mammalian PGI stimulated the motility of NIH-3T3 fibroblasts. The conserved active site of PGI is therefore not sufficient for receptor binding and cytokine activity of PGI. However, synthetic peptides corresponding to distinct peripheral mammalian PGI sequences did not inhibit internalization of mammalian PGI. Our data therefore argue that the cytokine activity of PGI is specific to mammalian PGI but cannot exclude the possibility that the receptor binding motif of PGI is complex and includes elements within and without the active site.
The function that stimulates a cell to grow or proliferate. Most growth factors have other actions besides the induction of cell growth or proliferation.
Interacting selectively and non-covalently with any monosaccharide. Monosaccharides are the simplest carbohydrates; they are polyhydroxy aldehydes H[CH(OH)]nC(=O)H or polyhydroxy ketones H[CHOH]nC(=O)[CHOH]mH with three or more carbon atoms. They form the constitutional repeating units of oligo- and polysaccharides.
The chemical reactions and pathways involving glucose 6-phosphate, a monophosphorylated derivative of glucose with the phosphate group attached to C-6.
The chemical reactions and pathways resulting in the breakdown of a monosaccharide (generally glucose) into pyruvate, with the concomitant production of a small amount of ATP. Glycolysis begins with phosphorylation of a monosaccharide (generally glucose) on the sixth carbon by a hexokinase, and ends with the production of pyruvate. Pyruvate may be converted to ethanol, lactate, or other small molecules, or fed into the TCA cycle.
A new variant of glucosephosphate isomerase (GPI) associated with hemolytic anemia, mental retardation, and muscular hypotonia is described. The defective enzyme showed increased affinity for fructose-6-phosphate (F-6-P), decreased affinity for glucose-6-phosphate (G-6-P) altered electrophoretic and isoelectrofocusing patterns, and shift to the left of the precipitin curve. The enzyme was stable under all the conditions tested (heat, urea, guanidine-HCl, and storage). Optimum pH, Ki for 6-phosphogluconic acid (6-PGA) and for erythrose-4-phosphate (E-4-P), molecular weight, GPI-related antigen concentration, immunodiffusion pattern, and immunoinactivation were in the normal range. This is the first example of the association of a stable mutant GPI with severe hemolytic anemia. Enzyme instability has been present in all previously reported cases.
Neuroleukin is a lymphokine product of lectin-stimulated T cells that induces immunoglobulin secretion by cultured human peripheral blood mononuclear cells. Neuroleukin acts early in the in vitro response that leads to formation of antibody-secreting cells, but continued production of immunoglobulin by differentiated antibody-secreting cells is neuroleukin-independent. Although the factor is not directly mitogenic, cellular proliferation is a late component of the response to neuroleukin. Neuroleukin does not have B-cell growth factor (BCGF) or B-cell differentiation factor (BCDF) activity in defined assays. Neuroleukin-evoked induction of immunoglobulin secretion is both monocyte- and T-cell-dependent.
The chemical reactions and pathways resulting in the formation of methylglyoxal, CH3-CO-CHO, the aldehyde of pyruvic acid.
IEAOrtholog Compara
Negative regulation of cysteine-type endopeptidase activity involved in apoptotic processdefinition[GO:0043154]‹silver
Any process that stops, prevents, or reduces the frequency, rate or extent of a cysteine-type endopeptidase activity involved in the apoptotic process.
Protein involved in angiogenesis, the sprouting or splitting of capillaries from pre-existing vasculature. Angiogenesis plays an important role for example during embryonic development, normal growth of tissues and maintenance of the normal vasculature, wound healing, tumor growth and metastasis.
Protein involved in the biosynthesis of "new" glucose from such noncarbohydrate precursors as pyruvate, lactate, certain amino acids and intermediates of the tricarboxylic acid cycle.
Protein involved in the anaerobic enzymatic conversion of glucose to lactate or pyruvate, resulting in energy stored in the form of adenosine triphosphate (ATP), as occurs in skeletal muscle and in embryonic tissue.
Small secreted proteins from higher eukaryotes which affect the growth, division and functions of other cells, e.g. interleukins, lymphokines, TNF and interferons. Generally, growth factors are not classified as cytokines, though TGF is an exception. Chemokines are a subset of cytokines. They differ from classical hormones in that they are produced by a number of tissues or cell types rather than by specialized glands. They generally act locally in a paracrine or autocrine rather than endocrine manner.
Protein which, by binding to a cell-surface receptor, triggers an intracellular signal-transduction pathway leading to differentiation, proliferation, or other cellular response.
Enzyme that catalyzes the 1,1-, 1,2- or 1,3-hydrogen shift. The 1,1- hydrogen shift is an inversion at an asymmetric carbon center (racemases, epimerases). The 1,2-hydrogen shift involved a hydrogen transfer between two adjacent carbon atoms, one undergoing oxidation, the other reduction (aldose-ketose isomerases). The 1,3-hydrogen shifts are allylic or azaallylic (when nitrogen is one of the three atoms) isomerizations.
A reference proteome is a set of protein sequences derived from a complete proteome which constitutes a defined standard for a particular user community. Reference proteomes are manually defined according to a number of criteria. They cover the proteomes of well- studied model organisms and other proteomes of interest for biomedical and biotechnological research. Reference proteomes have been selected to provide broad coverage of the tree of life, and constitute a representative cross-section of the taxonomic diversity to be found within UniProtKB.