Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P06889 (Mol)
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Protein synthesis has been studied in a cell-free system from chick embryo, in the presence of homologous RNA isolated from free and endoplasmic reticulum-bound polyribosomes. The two RNA fractions showed equal activities in total protein synthesis. However, while the RNA from bound polyribosomes mainly supported synthesis of high molecular weight, TCA-insoluble polypeptides, the RNA from free polyribosomes was more active in the synthesis of low molecular weight, TCA-soluble polypeptides. Optimal conditions for translation of the two RNA's under study were different when studied in a cell-free system with reduced content of endogenous matrix. Collagen synthesized in the system was identified by collagenase digestion. Collagen synthesis was demonstrated only in the presence of RNA from endoplasmic reticulum-bound polyribosomes, and represented 16-19% of total protein synthesis.
Mol Biol 1975 Jan
PMID:Protein biosynthesis in a homologous, cell-free system in the presence of chick embryo RNA isolated from free and membrane-bound polyribosomes. 16 98

Collagen mRNA has already been purified and characterized by us. Its purity has now been enhanced by two different methods. Gel electrophoresis shows in either method, a single peak with the same mobility already reported: 1.05 X 10(6) daltons. Base composition analyses of collagen mRNA purified by either method were almost identical. Chemical analyses of the isolated polyadenylic acid stretch show that it is, 0.48 X 10(5) daltons-long, (about 140 nucleotides-long), contains 75% AMP, and is located at the 3' end of the polymer.
Mol Biol Rep 1976 Jul
PMID:Further studies on collagen mRNA: partial chemical characterization and polyadenylic acid sequence. 95 18

The periodic protein collagen is of special interest for the study of the relationship which exists between the structure of a protein and that of its mRNA, because oligopeptides containing glycine, proline (hydroxyproline) and alanine occur with great frequency in it. Collagen is particularly rich in these amino acids, which have codons containing only G and/or C in the obligatory first and second positions. If unlimited choice of codons for all amino acids were to occur, the stretch of mRNA coding for an alpha-chain should contain about 40% G and 31% C (Bachra et al., 1974). These high values suggest that a considerable degree of secondary structure will occur, unless selective codon use would result in the avoidance of G and C in optional third codon positions. In the present paper putative secondary structure formation in collagen mRNA was studied. This was done by studying the positions and frequencies of hairpin structures which could contain stem sections composed of the coding triplets of the above mentioned amino acids and hairpin sections of 4-40 bases. Calculation of the free energy contributions of such hairpin structures, using published values for the contributions of base-pair stacking, hairpin, bulge and interior loops and also taking into account the possible minimum number of base-pairs required for helix nucleation from a single-strand RNA (3 adjacent AU-pairs or 1 or 2 adjacent GC-pairs) led to the following conclusions. A considerable number of alternative, mutually exclusive hairpins can be constructed.
J Mol Evol 1976 Aug 03
PMID:Self complementarity in messenger RNA of collagen. I. Possible hairpin structures in regions coding for oligopeptides of glycine, proline (hydroxyproline) and alanine. 96 90

Patients with diabetes often develop complications involving collagen-containing connective tissues. Previous in vitro studies have demonstrated that glucose inhibits collagen fibril formation and subsequent cross-linking. Collagen with diminished cross-linking is more susceptible to collagenolytic degradation. This may underlie the decreased collagen levels. To test this hypothesis, D-glucose and its two analogs, L-glucose and 2-deoxy-D-glucose, were used in chick calvaria organ cultures to examine parameters of collagen metabolism. L-Glucose is not used by the cell and functions as an extracellular glucose-like molecule, while 2-deoxy-D-glucose inhibits normal D-glucose uptake by blockading the glucose transport mechanism. Each of these three sugars had the ability to inhibit collagen fibril formation. D-Glucose stimulated collagen synthesis; L-glucose had no effect; and deoxyglucose inhibited collagen synthesis. D-Glucose was able to reverse the inhibitory effect of deoxyglucose. D-Glucose did not change levels of degradation of newly synthesized collagen while both L-glucose and deoxyglucose stimulated collagen degradation. When glucose transport was inhibited by deoxyglucose, collagen degradation was further enhanced. We suggest that decreased collagen levels in the connective tissues of diabetics may result from a combination of inhibition of collagen fibril formation and subsequent cross-linking, as well as increased collagen degradation.
Exp Mol Pathol 1992 Dec
PMID:Glucose and glucose analogs modulate collagen metabolism. 128 72

Basement membranes are thin layers of a specialized extracellular matrix that form the supporting structure on which epithelial and endothelial cells grow, and that surround muscle and fat cells and the Schwann cells of peripheral nerves. One common denominator is that they are always in close apposition to cells, and it has been well demonstrated that basement membranes do not only provide a mechanical support and divide tissues into compartments, but also influence cellular behavior. The major molecular constituents of basement membranes are collagen IV, laminin-entactin/nidogen complexes, and proteoglycans. Collagen IV provides a scaffold for the other structural macromolecules by forming a network via interactions between specialized N- and C-terminal domains. Laminin-entactin/nidogen complexes self-associate into less-ordered aggregates. These two molecular assemblies appear to be interconnected, presumably via binding sites on the entactin/nidogen molecule. In addition, proteoglycans are anchored into the membrane by an unknown mechanism, providing clusters of negatively charged groups. Specialization of different basement membranes is achieved through the presence of tissue-specific isoforms of laminin and collagen IV and of particular proteoglycan populations, by differences in assembly between different membranes, and by the presence of accessory proteins in some specialized basement membranes. Many cellular responses to basement membrane proteins are mediated by members of the integrin class of transmembrane receptors. On the intracellular side some of these signals are transmitted to the cytoskeleton, and result in an influence on cellular behavior with respect to adhesion, shape, migration, proliferation, and differentiation. Phosphorylation of integrins plays a role in modulating their activity, and they may therefore be a part of a more complex signaling system.
Crit Rev Biochem Mol Biol 1992
PMID:Basement membrane proteins: structure, assembly, and cellular interactions. 130 19

Collagen is the most important component of the extracellular matrix of the myocardium; it supports the myocytes and maintains the architecture of the heart. Collagen also participates in the myocardial response to various forms of pressure overload. Increased tissue collagen content occurs as a result of spontaneous or experimental overload-induced myocardial hypertrophy. In order to determine the mechanisms responsible for the increased collagen deposition in experimental cardiac hypertrophy, we established monolayer cultures of fibroblasts isolated from normal adult rat myocardium and studied their growth and biosynthetic characteristics. These cells have a doubling time of about 20h and synthesize and secrete several collagenous and non-collagenous proteins. We found that type I collagen was the major collagenous product of these cells representing 80% of total newly synthesized collagen. Most of the newly synthesized collagen was secreted into the culture medium as intact and partially cleaved procollagens. About 20% of the total collagen synthesized was type III collagen which was also secreted into the medium as a procollagen. A small proportion of type V collagen (less than 5%) was also synthesized by these cultures. Fibronectin which was identified by its mobility in SDS gel electrophoresis was quantified by immunoprecipitation with specific antisera and was the most abundant non-collagenous protein synthesized by these cells. Northern blot hybridization analysis demonstrated that these cells expressed transcripts for alpha 1 chains of types I and III collagen and for fibronectin.
J Mol Cell Cardiol 1992 Jul
PMID:Growth properties and biochemical characterization of collagens synthesized by adult rat heart fibroblasts in culture. 140 9

Collagen gene expression during volume overload-induced cardiac hypertrophy was investigated in adult male rats. Hypertrophy of the left ventricle (22%) and right ventricle (37%) occurred following 27 days continuous exposure to 700 ppm carbon monoxide; hematocrit increased nearly 47%. To examine potential cellular and molecular control of restructuring in the heart, we investigated the expression of two specific procollagen mRNAs for collagen types which have different structural-functional roles [Type I (alpha-1) & Type IV]. Type I (interstitial) mRNA levels increased at least 100% relative to controls within 3 days of initial exposure to 700 ppm CO, then declined afterwards; type IV (basement membrane) mRNA levels increased more modestly at first, and increased further afterwards. The ratio of type I/type IV RNA's also increased initially, then later declined, with the greatest differences in the relative responses of type I and IV mRNAs seen in the right ventricle. These data suggest that types I and IV collagen mRNA expression is not coordinately expressed during this type of volume overload-induced hypertrophy in rat heart.
Mol Cell Biochem 1992 Jan 15
PMID:Non-coordinate expression of collagen mRNAs during carbon monoxide-induced cardiac hypertrophy. 153 18

Human lung fibroblasts differing in C1q binding, steady-state levels of collagen synthesis, and other functional properties were isolated. Explants of normal human lung specimens were cultured in medium containing complement-inactivated plasma-derived human serum or complete human serum. Cells obtained were treated with C1q and fluorescein isothiocyanate-anti-C1q antibody and separated based on fluorescence intensity in a fluorescence-activated cell sorter (FACS). FACS profiles showed that fibroblasts obtained in the presence of plasma-derived serum (HF cells) displayed higher fluorescence intensity than those obtained in complete serum (LF cells). The unsorted and sorted HF and LF fibroblasts retained their respective fluorescence phenotypes after subculture. The LF fibroblasts proliferated faster than HF cells and contained more cycling cells. However, whereas the sorted HF cells grew normally, sorted LF cells grew poorly. Collagen production and pro alpha l[I] mRNA levels in HF cells were 2.6 +/- 0.7 and 2.1 +/- 0.6 times as high as LF cells (n = 4). Collagen synthesis in both HF and LF cells was stimulated by transforming growth factor-beta and inhibited by interferon-gamma, but the stimulation was greater and inhibition less in LF cells. Our results indicate that C1q binding and the type of C1q receptors can serve as markers for fibroblast subpopulations differing in collagen synthesis, and that selection of subpopulations and their differential sensitivity to regulatory molecules can contribute to collagen alterations associated with inflammation, fibrosis, and other acquired diseases.
Am J Respir Cell Mol Biol 1992 Apr
PMID:Human lung fibroblast subpopulations with different C1q binding and functional properties. 155 Jun 83

The Kunitz-type protease inhibitor is one of the serine protease inhibitors. It is found in blood, saliva, and all tissues in mammals. Recently, a Kunitz-type sequence was found in the protein sequence of the amyloid beta precursor protein (beta APP). It is known that beta APP accumulates in the neuritic plaques and cerebrovascular deposits of patients with Alzheimer's disease. Collagen type VI in chicken also has an insertion of a Kunitz-type sequence. To elucidate the evolutionary origin of these insertion sequences, we constructed a phylogenetic tree by use of all the available sequences of Kunitz-type inhibitors. The tree shows that the ancestral gene of the Kunitz-type inhibitor appeared about 500 million years ago. Thereafter, this gene duplicated itself many times, and some of the duplicates were inserted into other protein-coding genes. During this process, the Kunitz-type sequence in the present beta APP gene diverged from its ancestral gene about 270 million years ago and was inserted into the gene soon after duplication. Although the function of the insertion sequences is unknown, our molecular evolutionary analysis shows that these insertion sequences in beta APP have an evolutionarily close relationship with the inter-alpha-trypsin inhibitor or trypstatin, which inhibits the activity of tryptase, a novel membrane-bound serine protease in human T4+ lymphocytes.
J Mol Evol 1992 Jun
PMID:Evolutionary origin of a Kunitz-type trypsin inhibitor domain inserted in the amyloid beta precursor protein of Alzheimer's disease. 159 45

Collagen synthesized by tissue minces from lungs of rats administered 1 unit of bleomycin by intratracheal instillation 1 or 2 wk earlier contained relatively more hydroxylysine than did collagen made by lungs from saline-instilled control animals. Most, if not all, of the relative increase in lysine hydroxylation could be localized to the alpha 1 (I) chain of type I collagen. Lung homogenates from bleomycin-treated rats showed increased activity of lysyl hydroxylase (EC 1.14.11.4), the enzyme catalyzing the conversion of collagen-bound lysine to hydroxylysine. Thus, the increased hydroxylation of lysine and of lysine-derived cross-links previously observed in collagen of diseased human lungs and in animal models of lung fibrosis is reflected in an in vitro system.
Am J Respir Cell Mol Biol 1990 Jun
PMID:Hydroxylation of collagen by lungs of rats administered bleomycin. 169 82


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