Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.3.1.28 (chloramphenicol acetyltransferase)
 5,100 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Cyclic mechanical strain (1 Hz) causes a mitogenic response in neonatal rat vascular smooth muscle cells due to production and secretion of PDGF. In this study, the mechanism for sensing mechanical strain was investigated. Silicone elastomer strain plates were coated at varying densities with elastin, laminin, type I collagen, fibronectin, or vitronectin. Strain was applied by cyclic application of a vacuum under the dishes. Cells adhered, spread, and proliferated on each matrix protein, but the mitogenic response to strain was matrix dependent. Strain increased DNA synthesis in cells on collagen, fibronectin, or vitronectin, but not in cells on elastin or laminin. When strain was applied on matrices containing both laminin and vitronectin, the mitogenic response to strain depended upon the vitronectin content of the matrix. Fibronectin, in soluble form (0-50 micrograms/ml), and the integrin binding peptide GRGDTP (100 micrograms/ml) both blocked the mitogenic response to mechanical strain in cells grown on immobilized collagen. Neither soluble laminin nor the inactive peptide GRGESP blocked the response to strain. GRGDTP did not alter the mitogenic response to exogenous PDGF or alpha-thrombin but did prevent the secretion of PDGF in response to strain. Furthermore, GRGDTP, but not GRGESP, prevented strain-induced expression of a PDGF-A chain promoter 890 bp-chloramphenicol acetyltransferase construct that was transiently transfected into vascular smooth muscle cells. Finally, the response to strain was abrogated by antibodies to both beta 3 and alpha v beta 5 integrins but not by an antibody to beta 1 integrins. Thus interaction between integrins and specific matrix proteins is responsible for sensing mechanical strain in vascular smooth muscle cells.
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PMID:Mechanical strain of rat vascular smooth muscle cells is sensed by specific extracellular matrix/integrin interactions. 759 24

Aeromonas hydrophila is an important pathogen of fish, and its high-virulence strains display a two-dimensional paracrystalline layer (S-layer) on their outermost surfaces. The nucleotide sequence of a 4.1-kb region located 700 bp upstream of the A. hydrophila TF7 S-layer protein gene (ahsA) has been determined. A sequence analysis of the region revealed the presence of three complete open reading frames ending in a gene encoding a 79.8-kDa polypeptide that shows high homology to the PulD family of secretion proteins. The sequenced region displays both organizational and sequence homology to the Xanthomonas campestris pv. campestris Xps secretory system. Insertional inactivation of the spsD (S-protein secretion D) gene showed that the loss of expression of the PulD homolog coincided with the localization of the S-protein in the periplasm and the loss of the S-layer from the surface of the bacterium. However, the secretion of the enzymes hemolysin, amylase, and protease was unaffected in the mutant with the nonfunctional spsD gene, as was the export of flagella and fimbrial proteins. Southern blot analysis showed that the spsD gene was not conserved among all strains of S-protein-producing A. hydrophila or Aeromonas veronii biotype sobria. Use of the promoterless chloramphenicol acetyltransferase gene showed that unlike pulD and its homologs, spsD contains its own promoter. A. hydrophila has been shown to contain the exe operon, which is responsible for the secretion of a number of extracellular enzymes in this bacterium. A fragment of DNA was generated from the exeD gene of A. hydrophilia Ah65 by PCR and was subsequently used in hybridization studies to probe the chromosome of A. hydrophila TF7. The presence of an exeD homolog in A. hydrophila TF7 was found; therefore, the spsD gene encodes a second pulD homolog that displays a high specificity for the secretion of the S-protein. This gene appears to be part of a second terminal branch of the general secretory pathway in A. hydrophila.
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PMID:A specific PulD homolog is required for the secretion of paracrystalline surface array subunits in Aeromonas hydrophila. 760 63