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Biomedical subjects

E Kominami

Publications and source records attributed to E Kominami.

At least 163 records · Page 9Linked to original sources
PubMed1989

Immunocytochemical localization of angiotensinogen and cathepsins B, H, and L in rat hepatocytes, with special reference to degradation of angiotensinogen in lysosomes after colchicine.

We examined the effects of bilateral nephrectomy and colchicine treatment on localization and content of angiotensinogen and cathepsins B, H, and L in rat liver using immunohistochemistry, radioimmunoassay, and enzyme assay. Angiotensinogen content increased in the liver of colchicine-treated rats, whereas a clear-cut increase was not detected in the liver of nephrectomized rats. This tendency was consistent with the immunocytochemical results; only perivenous hepatocytes in control and nephrectomized rats were diffusely immunostained by anti-angiotensinogen, whereas perivenous and periportal hepatocytes of colchicine-treated rats were strongly immunostained. Enzyme assay revealed no significant change in activities of cathepsins B, H, and L in liver extracts under these experimental conditions. Immunocytochemical localization of these cysteine proteinases in hepatocytes after colchicine treatment was more widespread in the cytoplasm than that in the control hepatocytes. By electron microscopy, angiotensinogen was localized in smaller vesicles and some larger vesicles (lysosomes) of hepatocytes after colchicine treatment. Double immunostaining demonstrated co-localization of cathepsins B, H, and L with angiotensinogen in lysosomes. These results suggest that cathepsins B, H, and L play a role in the degradation of excess angiotensinogen in hepatocytes of rats after colchicine treatment.

Angiotensinogen↗
PubMed1989

An immunocytochemical study on co-localization of cathepsin B and atrial natriuretic peptides in secretory granules of atrial myoendocrine cells of rat heart.

To examine localization of cathepsin B, a representative lysosomal cysteine protease, in atrial myoendocrine cells of the rat heart, immunohistochemistry at the light and electron microscopic level was applied to the atrial tissue, using a monospecific antibody for rat liver cathepsin B. In serial semi-thin sections, immunoreactivity for cathepsin B and atrial natriuretic peptides (ANP) was detected in the para-nuclear region of atrial myoendocrine cells. Several large granules and many fine granules in the region of the cells were positively stained by the cathepsin B antibody. Gold particles indicating cathepsin B antigenicity labeled secretory granules in the cells, which were also labeled by those indicating ANP, using thin sections of the Lowicryl K4M-embedded material. Moreover, some granules labeled densely by immunogold particles for cathepsin B seemed to be lysosomes. By double immunostaining using thin sections of the Epon-embedded material, gold particles indicating cathepsin B and ANP antigenicities were co-localized in secretory granules of the cells. By enzyme assay, activity of cathepsin B was three times higher in atrial tissue than ventricular tissue. The results suggest that co-localization of cathepsin B and ANP in secretory granules is compatible with the possibility that cathepsin B participates in the maturation process of ANP.

Animals↗
PubMed1989

Immunocytochemical localization of cathepsins B, H, L, and T4 in follicular cells of rat thyroid gland.

To localize cathepsins B, H, and L in follicular cells of rat thyroid gland, we applied immunocytochemistry to the thyroid tissue using their respective monospecific antibodies. On serial semi-thin sections, cathepsins B, H, and L were localized in granules of various sizes located throughout the cytoplasm, whereas T4 was detected in larger granules located in the apical and supranuclear regions. By electron microscopy, cathepsins B, H, and L were localized in large less-dense granules (so-called colloid droplets) and in dense bodies of various sizes, whereas T4 was localized more intensely in large less-dense granules than in smaller dense bodies. By double immunostaining using an immunogold method, cathepsins H and B or L were co-localized in the same cytoplasmic granules. Moreover, immunoblotting demonstrated that proteins similar to cathepsins B, H, and L in the liver are present in the thyroid gland. These results suggest that cathepsins B, H, and L participate not only in degradation of thyroglobulin but in maturation of thyroid hormones, although it remains unknown whether all of them participate in the maturation process.

Animals↗
PubMed1989

Cysteine proteinase-inhibitory activity of ras gene product is not affected by mutations at GTPase-activating protein-binding sites.

We have investigated the proteinase-inhibitory activity against cathepsin L of some c-Ha-ras gene products (p21s) with point mutations at position 12, 33 or 35, which affect the interaction with GTPase-activating protein (GAP). All of the full-length p21s examined showed similar inhibitory activities irrespective of the point mutation and the transforming activity. These results suggest that mutations at GAP-interacting sites have no effect on the proteinase-inhibitory activity of p21s and that the proteinase-inhibitory activity alone is not sufficient for the transformation caused by p21s.

Amino Acid Sequence↗
PubMed1989

Potentiation of cysteine proteinase-inhibitor activity of full-length Ha-ras oncogene products by denaturation-renaturation.

We have investigated protease-inhibitory activity against cathepsin L of human and murine Ha-ras oncogene products (p21s) produced by Escherichia coli. The inhibitory activity of full-length p21s was much weaker than that of truncated p21s, however, the inhibitory activity was potentiated after denaturation with 8 M urea and 2 M NaCl followed by renaturation. These suggest that p21 can be folded into multiple three-dimensional conformations which have different protease-inhibitory activities.

Animals↗
PubMed1988

Enzyme immunoassay of medullasin in peripheral blood.

An enzyme immunoassay method for the determination of the amount of medullasin, a serine protease in granulocytes, was developed. Beads coated with IgG obtained from immunized rabbits were incubated with medullasin, Fab'-peroxidase conjugate was added, and peroxidase activity bound to beads was measured by a fluorophotometer. The amount of medullasin determined by this method correlated well with the value calculated from the protease activity measured by the conventional method. The minimum detectable amount of medullasin was 300 pg. Granulocytes obtained from patients with multiple sclerosis in active phase and those from patients with Behçet's disease in relapse showed elevated levels of medullasin as compared with normal controls. However, the amount of medullasin in granulocytes obtained from patients in remission revealed normal values. These results indicate that elevated levels of medullasin activity in granulocytes of these diseases in relapse is due to an increased amount of medullasin in granulocytes and that the normalization of medullasin activity in remission is the result of the decrease of the amount of medullasin in granulocytes.

Behcet Syndrome↗
PubMed1988

Total synthesis of the cystatin alpha gene and its expression in E. coli.

A gene encoding cystatin alpha has been chemically synthesized, cloned and expressed in E. coli. The gene of 318 base pairs was assembled by enzymatic ligation of 19 oligonucleotides and cloned into a pBR322-derived expression plasmid down stream of the tac promoter. The expression product of the synthetic gene has been purified by Sephadex G-50 column chromatography and shown to have the same properties as those of the authentic protein isolated from rat epidermis.

Amino Acid Sequence↗
PubMed1988

Degradation of epidermal growth factor receptors by cathepsin L-like protease: inhibition of the degradation by c-Ha-ras gene products.

Extract of NIH3T3 mouse fibroblasts contains a protease which can cleave epidermal growth factor receptor (EGF receptor). This protease was tentatively named cathepsin X and purified to near homogeneity. The characteristics of cathepsin X were similar to those of cathepsin L and the proteolytic activity of cathepsin X was inhibited by c-Ha-ras gene products.

Animals↗
PubMed1988

Biosyntheses and processing of lysosomal cysteine proteinases in rat macrophages.

The intracellular processing and release of three lysosomal cysteine proteinases, cathepsin B, H and L, by rat peritoneal macrophages were investigated by pulse-chase experiments. Newly synthesized procathepsins B (39 kDa), H(41 kDa) and L (39 kDa) after 15 min labeling were processed to the mature, single-chain enzymes within 1 h. The single-chain forms of cathepsin B, H and L were further processed to two-chain forms at different rates: conversion of cathepsin L to the two-chain form was rapid, whereas the conversions cathepsin B and H took at least 6 h. Macrophages released 30% of the procathepsins B and L, and 10% of the procathepsin H.

Animals↗
PubMed1988

Effect of proteinase inhibitors on intracellular processing of cathepsin B, H and L in rat macrophages.

The effects of various proteinase inhibitors on the processing of lysosomal cathepsins B, H and L were investigated in cultured rat peritoneal macrophages. The processing of newly synthesized pro-cathepsins B, H and L to the mature single-chain enzymes was sensitive to a metal chelator,1,10-phenanthroline, and a synthetic metalloendopeptidase substrate, Z-Gly-Leu-NH2, and insensitive to inhibitors of serine proteinases, aspartic proteinases and cysteine proteinases. Inhibitors of cysteine proteinases, E-64-d and leupeptin, inhibited the processing of the single-chain forms of cathepsins B, H and L to the two-chain forms. These results suggest that (a) metal endopeptidase(s) is (are) involved in the propeptide processing of cathepsin B, H and L, and that proteolytic cleavages of the mature single-chain cathepsins are accomplished by cysteine proteinases in lysosomes.

Animals↗
PubMed1988

Inhibition of cathepsin L-induced degradation of epidermal growth factor receptors by c-Ha-ras gene products.

The inhibitory activities of c-Ha-ras gene products (p21s) toward several cysteine proteinases have been investigated. The activity of cathepsin L was inhibited by p21s most effectively while those of cathepsin B and papain were slightly inhibited by p21s. p21s did not show any inhibitory activity toward cathepsin H. In order to connect the protease-inhibitor activity of p21s with cell growth, the degradation of epidermal growth factor receptors (EGF-receptors) was investigated. EGF-receptors were preferentially cleaved by cathepsin L but not by cathepsin B or H. The cleavage of EGF-receptors by cathepsin L was inhibited by p21s dose-dependently. These results raise the possibility that p21s can suppress the degradation of growth-related proteins such as EGF-receptors and thereby affect cell growth.

Carcinoma, Squamous Cell↗
PubMed1988

Immunolocalization of cathepsins B, H and L in skeletal muscle of X-linked muscular dystrophy (mdx) mouse.

The amounts of non-collagen proteins (muscle structural proteins) and the activity of creatine kinase were significantly decreased in muscles of 28-day-old mdx mice. The activities of lysosomal thiol proteases such as cathepsins B and L were increased in muscles of mdx mice at as early as 10 days of age. Endogenous thiol proteinase inhibitor and various lysosomal hydrolases also showed increased activities. The localization of cathepsins B, H and L, and endogenous thiol proteinase inhibitor was investigated using the respective specific antibodies. While only invading macrophages were stained strongly with anticathepsin B and H, and anti-thiol proteinase inhibitor antibodies, cathepsin L was localized in muscle cells as well as in invading macrophages. Cathepsin L in muscle cells itself may initially degrade muscle structural proteins, before lysosomal thiol proteases, mainly derived from macrophages, degrade them in skeletal muscles of mdx mice.

Age Factors↗
PubMed1988

Immunocytochemical localization of cathepsins B, H, and their endogenous inhibitor, cystatin beta, in islet endocrine cells of rat pancreas.

To determine the characteristics of lysosomes in rat islet endocrine cells, we examined the precise localization of cathepsins B, H, and L and their specific inhibitors, cystatins alpha and beta, using immunocytochemical techniques. By use of serial semi-thin sections, we detected immunoreactivity for cathepsin B in insulin-, glucagon-, somatostatin-, and pancreatic polypeptide-positive (PP) cells. Strong immunoreactivity for cathepsin H was seen in A-cells and weak immunoreactivity in PP cells, but none in others. Immunodeposits for cystatin beta were demonstrated in B-cells. Brief dipping of thin sections in 1% sodium methoxide before the following immunocytochemical reaction enhanced specific deposits of immunogold particles on the target organelles. Use of a double-immunostaining technique showed co-localization of insulin with cystatin beta in many secretory granules. This suggests that cystatin beta may regulate converting enzymes participating in the maturation process of insulin. By use of an immunogold technique, heterogeneous localization of cathepsins B and H in lysosomes was also found among islet cells at the light microscopic level. This may be due to the difference in peptides degraded in lysosomes among the cells.

Animals↗
PubMed1987

Molecular cloning and sequencing of cDNA for rat cathepsin H. Homology in pro-peptide regions of cysteine proteinases.

A cDNA for rat cathepsin H was isolated and sequenced. The deduced protein comprising 333 amino acid residues is composed of a typical signal sequence (21 residues), a pro-peptide region (92 residues) and a mature enzyme region (220 residues). The amino acid sequence in the pro-peptide region, in particular, residues Phe-(-41) to Ser-(-29) of cathepsin H, is highly homologous to the pro-peptide regions of other cysteine proteinases. This homologous region may play a role in the processing of cysteine proteinases.

Amino Acid Sequence↗