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At least 19 recordsLinked to original sources
PubMed1992

Functional molecular mass of the 14C-azidobenzamidotaurocholic acid binding proteins in hepatocellular bile acid transport systems.

The apparent target size of 14C-azidobenzamidotaurocholate binding proteins in basolateral rat liver plasma membranes (blPm) was determined by analysis of the radiation induced decrease of the binding of this photoreactive taurocholate analog to blPm. Radiation causes a dose-dependent mono-exponential reduction of binding of ABATC to the protein subunits with molecular masses of 48-50 and 52-54 kDa in SDS-PAGE. The minimal functional molecular mass of the 48-50 and 52-54 kDa ABATC binding proteins was determined to be 99 +/- 8.2 and 93.2 +/- 7 kDa, respectively.

Animals↗
PubMed2026

Translating functional molecular knowledge into crop-breeding success.

Historical plant breeding, which optimizes phenotypes through selective crossing guided by phenotypic evaluation and molecular markers, is limited by evolutionary constraints that hinder rapid crop improvement. A new paradigm, precision breeding, circumvents these limitations by targeting genetic variants through functional molecular knowledge. To generate this knowledge at scale, sequence-based deep learning leverages high-quality genome sequence data to predict variant effects at base-pair resolution. When linked to agronomically important traits, these predictions enable breeders to prioritize variants for precision selection or editing. Although it is still in the early stages of development, we foresee three key applications for this approach: introgressing genes from distant breeding pools, purging deleterious mutations and designing new plant ideotypes. Looking ahead, refined computational models will facilitate targeted editing and the systematic redesign of complex physiological processes to address emerging breeding goals under shifting environmental conditions.

Crops, Agricultural↗
PubMed1992

[Function, molecular structure and gene expression of insulin-like growth factors ].

In this short review, gene structure, transcriptional pattern, biological activity, specific receptors and binding proteins for insulin-like growth factors (IGF: IGF I and IGF II) are explained. In spite of their close similarity in both gene and peptide structures, their receptors are completely distinct from each other in molecular structure and in signal transduction. Expression of IGF function in vivo is strongly restricted by plasma binding proteins.

Carrier Proteins↗
PubMed1992

[Function, molecular structure and gene expression of fibroblast growth factor (FGF/HBGF)].

The structure and function of members of the fibroblast growth factor (FGF) gene family and their receptors are reviewed. All the member of this gene family bind heparin, and therefore, are also called the as heparin-binding growth factor (HBGF). In this review, the structural features of FGF/HBGF are summarized first, and general features of the structure and function of their receptors are then described briefly. After biological effects of FGF/HBGF on adult-type tissues and cultured cells are reviewed, effects of FGF on the mesodermal induction in amphibian (Xenopus laevis) embryonic system are reviewed in more detail. Emphasis is given on the experiments with Xenopus animal cap assay system and also on the injection into Xenopus fertilized eggs of mRNA of dominant defect mutant of FGF receptor, which leads to the formation of embryos with abnormal axial mesoderm.

Animals↗
PubMed1992

[Function, molecular structure and gene expression of interferons].

Interferon is a key substance of the cytokine network, and is functioning not only as the virus inhibitory factor, but also as the factor for differentiation, development, and homeostasis of animals, including man. The molecular structure, induction mechanisms, interaction with receptor, and antiviral action mechanisms of IFN were reviewed. 1. Molecular structure of IFN IFNs are now divided into 4 types--alpha, beta, gamma, omega--according to antigenicities of IFN proteins, and to base sequence of their genes. The omega type was established officially on 1990 by the Nomenclature Committee of International Society for Interferon Research (ISIR). Also, the genes for HuIFNs were named as follows; HuIFN-A for HuIFN-alpha, HuIFN-B for HuIFN-beta, HuIFN-G for HuIFN-gamma, and HuIFN-W for HuIFN-omega. Nevertheless, the names of Type I IFN and Type II IFN are still valuable, since members of Type I IFN, alpha, beta, and omega, are similar in their molecular structures, and they share the common receptor (Type I IFN receptor), on the other hand, HuIFN-gamma (the only one member of Type II IFN) has different characteristics from the other IFNs, and binds to its specific receptor (Type II IFN receptor). However, it has been reported that both N-terminal and C-terminal of IFN protein of all types, participate in the binding of IFN to its receptor. 2. Induction mechanism of IFN. The factors, IRF-1 and IRF-2, were found to play an important role in IFN induction.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMed1992

[Function, molecular structure and gene expression of IL-4].

Interleukin-4 (IL-4) is a T-lymphocyte-derived 20-kDa glycoprotein that has a broad spectrum of biological activity including growth and differentiation of T cells, B cells, mast cells, hematopoietic cells and non-hematopoietic cells. The biological effects of IL-4 are induced by binding to specific membrane receptors (IL-4R) on target cells. Molecular cloning of IL-4R revealed a novel cytokine receptor family, but not clues as to the signalling mechanism. The biochemical mechanism of IL-4 signal, induced by its specific binding, remains to be clarified. Recent studies on the physiological function of IL-4 are presented here.

Amino Acid Sequence↗
PubMed1992

[Function, molecular structure and gene expression regulation of transforming growth factor-beta (TGF-beta)].

Transforming growth factor-beta (TGF-beta) is a multifunctional peptide growth factor widely distributed in vertebrates and represents a prototype of a large family of structurally related factors that regulate various cellular functions, ranging from amphibian embryonal development to hormone production in the human pituitary. TGF-beta is a disulfide-bonded homodimer of a subunit of 12.5 kD that is derived from a much larger precursor. The amino acid sequences of TGF-betas are highly conserved among species, suggesting their physiological importance. TGF-beta was originally isolated from human platelets as a factor that induces anchorage-independent growth of normal fibroblasts. However, later studies have revealed that its major biological activities include inhibition of cell proliferation, and regulation of differentiation, cell adhesion and extracellular matrix deposition. There are three types of cellular receptors that bind TGF-beta. Type II receptor, of which cDNA was recently cloned, is a functional serine/threonine kinase and is thought to be involved in the TGF-beta-mediated signal transduction pathway. The importance of TGF-beta in clinical medicine will increase not only as it is a promising therapeutic drug, but also as its excessive activity can be the cause of various human fibrotic diseases.

Amino Acid Sequence↗
PubMed1992

[Function, molecular structure and gene expression regulation of erythropoietin].

Erythropoietin (EPO) is a glycoprotein hormone which enhances red blood cell production by stimulating growth and differentiation of erythroid progenitor cells. Recombinant human EPO (huEPO), expressed in CHO cells, is highly similar to urinary huEPO with respect to both structural and functional properties. EPO production is primarily localized to peritubular interstitial cells in the cortex of the kidney. Increased EPO production due to anemia seems to be correlated with increased numbers of EPO-producing cells rather than with increased production by the individual EPO-producing cells. A heme protein is proposed to be the oxygen sensor. Tissue-specific and hypoxia-inducible expression of EPO gene is governed by multiple regulatory elements. Murine CFU-E from the spleens of mice, infected with the anemia-inducing strain of Friend virus, differentiate into reticulocytes in response to EPO. EPO appears to prevent CFU-E from programmed death (apoptosis). The gene for mouse EPO receptor produces 65 Kd protein on the cell surface. This protein seems to be specifically associated with another 100 Kd and/or 85 Kd proteins. The gene for human EPO receptor was also cloned, based on its similarity to murine counterpart. EPO receptor belongs to a novel class of receptors termed the cytokine receptor superfamily.

Animals↗
PubMed1992

[Function, molecular structure and gene expression regulation of tumor necrosis factor and lymphotoxin].

Tumor necrosis factor (TNF, also called TNF-alpha) and lymphotoxin (LT, TNF-beta) have 32% homology in their primary structures, and it has recently been clarified that they also have closely related tertially structures. These two related cytokines share various biological functions, such as cytotoxic effect, immunomodulating effect, etc. although they produce different effects on several lymphoid, endothelial, and other cellular targets. In this paper, the structures of the two cytokines and their receptor binding sites are described. Furthermore, the structures of the two types of TNF receptors, as well as their role in TNF mediated signal transduction, and possible second messengers responsible for TNF action are also discussed.

Humans↗
PubMed1992

[Function, molecular structure and gene expression regulation of LD78].

LD78 is a member of a new cytokine superfamily, consisting of at least twelve small proteins, which are involved in inflammation and cell growth. Depending on their primary structure, these cytokines can be divided into two families, one of which contains LD78 and is known as the CC family. The protein and gene structures and the physiological functions of LD78 in comparison with the other CC family members are summarized here. Furthermore, the generation mechanism of the three LD78 genes and their expression are discussed.

Amino Acid Sequence↗
PubMed1992

[Function, molecular structure and gene expression of granulocyte colony-stimulating factor].

Human granulocyte colony-stimulating factor, a 19KD glycoprotein consisting of 174 amino acids, is one of the physiological regulators mainly produced by monocytes-macrophages, fibroblasts, and endothelial cells, under various stimulations such as neutropenias and infections. The molecule specifically and markedly stimulates the production of neutrophils associated with an expansion of the hemopoietic stem cells/progenitor cells, proliferates myeloid leukemia cells, releases these cells into blood, and elevates the functional activities of neutrophils. Under the favor of the activities, recombinant human granulocyte colony-stimulating factor has now become an epoch-making agents for the treatment of various disorders.

Amino Acid Sequence↗
PubMed1992

[Function, molecular structure and gene expression regulation of receptor for D-factor/LIF].

Differentiation-stimulating factor (D-factor)/leukemia inhibitory factor (LIF) is a cytokine inducing differentiation of mouse myeloid leukemic M1 cells. IL-6, oncostatin M (OSM) and G-CSF also induce differentiation of M1 cells. These four cytokines are suggested to be members of a single cytokine family. The LIF receptor is structurally related to the gp130 signal-transducing component of the IL-6 receptor and to the G-CSF receptor. The high-affinity receptors for LIF, OSM and IL-6 share the common subunit, gp130. This provides an explanation for the functional redundancy of those cytokines.

Animals↗
PubMed1992

[Function, molecular structure and gene expression regulation of Platelet-derived growth factor].

Platelet-derived growth factor (PDGF) is a cationic glycoprotein of approximately 30 kDa, composed of two subunits. These subunit chains are termed A (18 kDa) and B (12-14 kDa) with high homology of the peptide sequences, including 8 cysteine residues at identical positions. Three isoforms of PDGF, AA, BB homodimers and AB heterodimer are distributed in the different tissues and cell lines suggesting that these isoforms have different functions. Two types of PDGF receptors alpha, and beta with Mr of 160-180 kDa are seen on the cell surface. PDGFR alpha can bind to both A and B subunits of the PDGD, while PDGFR beta, only B subunit. PDGF (AA) combines alpha alpha, PDGF (AB) makes dimers of alpha alpha and alpha beta, and PDGF (BB) can make three types of dimers, alpha alpha, alpha beta, and beta beta. These dimeric PDGFRs are active forms and phosphorylate its own domain and other neighbor specific proteins. The substrates of the receptor kinase are phospholipase C-gamma, GTPase activating protein (GAP), serine/threonine kinase Raf-1 and others. These molecules are thought to transfer information of the PDGFs on its receptors to the nucleus.

Amino Acid Sequence↗
PubMed1977

The molecular function of hemoglobin as reflected in ligand binding data: analysis of data on erythrocytes.

Hemoglobin oxygen binding data on erythrocytes at diffrent pH, PCO2 and bisphosphoglycerate concentrations have been analyzed in terms of an extended version of the Herzfeld-Stanley model of 1972. The binding of oxygen to subunits when the tetramer is in the quaternary oxy conformation was found to be insensitive to moderate changes in pH and pCO2 (0.71 +/- 0.05 mm Hg-1). Utilizing this circumstance it has been possible to obtain, for the first time, unique estimates of energy parameters related to hemoglobin cooperativity and effector action. At 37 degrees C, pH 7.2 and pCO2 22 mm Hg the following parameter values were obtained: The allosteric constant: (1.5 + 0.4)-10(4); the oxygen binding constant of the deoxy state: (5.4 +/- 0.3).10(-3) mm Hg-1; the 2,3-bisphosphoglycerate binding constants: (3.3 +/- 1.3).10(3)1. mol-1(deoxy), (1.3 +/- 0.5).10(2)1. mol-1 (oxy). Quarternary transition most likely takes place after binding of the second O2 molecule. Following the concepts of Perutz the results suggest that (1) protons and carbon dioxide act as constraint effectors and/or as quaternary effectors; (2) the difference in total conformational energy between the two quaternary ligand-free states is almost exclusively confined to molecular constraints and very little to the difference in quaternary conformational energy. The consistency of the results indicate that the model may be regarded as a useful tool for the description of the functional interrelations in the hemoglobin oxygenation process as reflected in oxygen binding data.

Binding Sites↗
PubMed1992

[Function, molecular structure and gene expression of interleukin-1].

Recent cloning of human and murine IL-1 receptor (IL-1R) has revealed that there are at least two type of IL-1R: type I IL-1R is detected on T cells and fibroblasts and consists of 552 AAs with a cytoplasmic domain of 213 AAs, while type II is detected on B cells and monocytic cell lines and consists of 398 AAs with a short stretch intracytoplasmic domain of 29 AAs. Extracytoplasmic portion of IL-1R has some homology with vaccinia virus B15 Ag or fibroblast protein ST-2, while cytoplasmic portion has considerable similarity with Drosophila toll gene. By transfecting murine type I IL-1R cDNA into a human Jurkat cell line, structural and functional potion required for the IL-1 signal transduction is determined. At least broad portion of cytoplasmic domain including 364-474 AAs from N-terminus are found to be essential, while PKC acceptor site (Ser-431 and Ser-509), and PKA acceptor site (Ser-528) are not essential for the IL-8 gene expression.

Amino Acid Sequence↗
PubMed1990

[The molecular function of oncogenes].

Cancer represents a disruption of the processes in normal cells. To understand cancer, and thereby develop effective treatment, it is necessary to learn about normal reactions in the cells, and their connections. Thus cancer research has been an important source of knowledge about normal cells. Oncogenes are genes that transform normal cells into cancer cells. More than 60 oncogenes have been discovered, and many malignant diseases have been linked to these genes. Human cells contain a normal version of oncogenes, known as protooncogenes, which participate in the normal, cellular processes. This discovery has been of major importance for our understanding of cancer and molecular genetics.

Genes, Tumor Suppressor↗
PubMed1992

Molecular, functional and structural properties of an archaebacterial elongation factor 2.

The elongation factor 2 (aEF-2) from the extreme thermo-acidophilic archaebacterium Sulfolobus solfataricus, is the only cytosolic target protein which is ADP-ribosylated by diphtheria toxin in presence of NAD. Once ADP-ribosylated, aEF-2 is no longer able to sustain poly(Phe) synthesis in vitro. aEF-2 displays a great thermoresistance: at the growth temperature of the archaebacterium, 87 degrees C, its half-life is 3 h. The amino acid sequence of the N-terminal region of aEF-2 has been determined up to residue 22. In the first 15 positions such a sequence is identical to that of EF-2 from Sulfolobus acidocaldarius and very similar to that of EF-2 from other archaebacteria or eukaryotes. The same is true for the primary structure of the peptide containing the ADP-ribosylation site. The fact that the primary structure of EF-2 at the ADP-ribosylation site is highly conserved ensures either the correct recognition of the histidine residue by the enzymes involved in its modification to diphthamide, or the proper interaction with the diphtheria toxin.

Adenosine Diphosphate↗