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41.
Uezu A Horiuchi A Kanda K Kikuchi N Umeda K Tsujita K Suetsugu S Araki N Yamamoto H Takenawa T Nakanishi H 《The Journal of biological chemistry》2007,282(36):26481-26489
SGIP1 has been shown to be an endophilin-interacting protein that regulates energy balance, but its function is not fully understood. Here, we identified its splicing variant of SGIP1 and named it SGIP1alpha. SGIP1alpha bound to phosphatidylserine and phosphoinositides and deformed the plasma membrane and liposomes into narrow tubules, suggesting the involvement in vesicle formation during endocytosis. SGIP1alpha furthermore bound to Eps15, an important adaptor protein of clathrin-mediated endocytic machinery. SGIP1alpha was colocalized with Eps15 and the AP-2 complex. Upon epidermal growth factor (EGF) stimulation, SGIP1alpha was colocalized with EGF at the plasma membrane, indicating the localization of SGIP1alpha at clathrin-coated pits/vesicles. SGIP1alpha overexpression reduced transferrin and EGF endocytosis. SGIP1alpha knockdown reduced transferrin endocytosis but not EGF endocytosis; this difference may be due to the presence of redundant pathways in EGF endocytosis. These results suggest that SGIP1alpha plays an essential role in clathrin-mediated endocytosis by interacting with phospholipids and Eps15. 相似文献
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T. Motoyama Makoto Fujiwara Nobuko Kojima Hiroyuki Horiuchi Akinori Ohta M. Takagi 《Molecular & general genetics : MGG》1997,253(4):520-528
We previously isolated three chitin synthase genes (chsA, chsB, and chsC) from Aspergillus nidulans. In the present work, we describe the isolation and characterization of another chitin synthase gene, named chsD, from A. nidulans. Its deduced amino acid sequence shows 56.7% and 55.9% amino acid identity, respectively, with Cal1 of Saccharomyces cerevisiae and Chs3 of Candida albicans. Disruption of chsD caused no defect in cell growth or morphology during the asexual cycle and caused no decrease in chitin content in hyphae.
However, double disruption of chsA and chsD caused a remarkable decrease in the efficiency of conidia formation, while double disruption of chsC and chsD caused no defect. Thus it appears that chsA and chsD serve redundant functions in conidia formation. 相似文献
44.
Scavenger receptors for oxidized and glycated proteins 总被引:16,自引:0,他引:16
Summary. Our present knowledge on chemically modified proteins and their receptor systems is originated from a proposal by Goldstein and Brown in 1979 for the receptor for acetylated LDL which is involved in foam cell formation, one of critical steps in atherogenesis. Subsequent extensive studies using oxidized LDL (OxLDL) as a representative ligand disclosed at least 11 different scavenger receptors which are collectively categorized as scavenger receptor family. Advanced glycation endproducts (AGE) and their receptor systems have been studied independently until recent findings that AGE-proteins are also recognized as active ligands by scavenger receptors including class A scavenger receptor (SR-A), class B scavenger receptors such as CD36 and SR-BI, type D scavenger receptor (LOX-1) and FEEL-1/FEEL-2. Three messages can be summarized from these experiments; (i) endocytic uptake of OxLDL and AGE-proteins by macrophages or macrophage-derived cells is mainly mediated by SR-A and CD36, which is an important step for foam cell formation in the early stage of atherosclerosis, (ii) selective uptake of cholesteryl esters of high density lipoprotein (HDL) mediated by SR-BI is inhibited by AGE-proteins, suggesting a potential pathological role of AGE in a HDL-mediated reverse cholesterol transport system, (iii) a novel scavenger receptor is involved in hepatic clearance of plasma OxLDL and AGE-proteins. 相似文献
45.
Scavenger receptor for malondialdehyde-modified high density lipoprotein on rat sinusoidal liver cells 总被引:1,自引:0,他引:1
M Murakami S Horiuchi K Takata Y Morino 《Biochemical and biophysical research communications》1986,137(1):29-35
We report here the presence of a membrane-associated receptor which mediates endocytic uptake of malondialdehyde-modified high density lipoprotein (MDA-HDL) on sinusoidal liver cells. Binding of [125I]MDA-HDL to the cells was followed by internalization and degradation in lysosomes. The binding and lysosomal degradation of [125I]MDA-HDL were effectively inhibited by unlabeled MDA-HDL and acetyl-HDL. However, formaldehyde-treated serum albumin or low density lipoprotein modified either by acetylation or malondialdehyde, ligands known to undergo receptor-mediated endocytosis by sinusoidal liver cells, did not affect the binding of [125I]MDA-HDL to the cells. These results indicate that a receptor for MDA-HDL is described as a distinct member among the scavenger receptors for chemically modified proteins. 相似文献
46.
Effect of catecholamine on aldosterone release in isolated rat glomerulosa cell suspensions 总被引:1,自引:0,他引:1
Effect of adrenergic activity on the adrenal steroidogenesis and the modulation by catecholamines of aldosterone release were studied in isolated rat adrenal cell suspensions. Isoproterenol, norepinephrine and epinephrine, but not dopamine, caused statistically significant increase in aldosterone release. Both prazosin (alpha 1 antagonist) and yohimbine (alpha 2 antagonist) suppressed the norepinephrine-induced aldosterone release in a dose dependent manner, respectively. Both atenolol (beta 1 antagonist) and ICI 118-551 (beta 2 antagonist) also blocked (-)-isoproterenol-induced aldosterone release in a dose dependent manner, respectively. Neither (-)-isoproterenol nor (+/-)-norepinephrine at concentrations of 10(-6) M potentiated aldosterone release stimulated by angiotensin II or ACTH. These results suggest that catecholamines stimulate aldosteroidogenesis, but it appears unlikely that aldosterone release induced by ACTH or angiotensin-II is modulated by adrenergic stimulation. 相似文献
47.
The aim of this study was to evaluate the difference in birth weight and gestation length between Japanese Black calves obtained from transfer of bovine embryos produced in vitro (IVP) and those developed in vivo (IVD). An additional objective was to clarify the sire effect on birth weight and gestation length and to examine the birth rate of heavier calves. Two Japanese Black bulls breed at our experimental station were used as a semen source for production of IVP and IVD embryos. Thirty-eight Japanese Black heifers and cows of various genetic backgrounds were used as embryo donors for IVD embryos. Ovaries for IVP embryos were collected at random at a local slaughterhouse from Japanese Black cattle of various genetic backgrounds. IVP embryos were produced using co-culturing with cumulus cells in 5% CS+TCM 199. Both the IVD and IVP embryos were transferred non-surgically to Holstein recipients on day 7+/-1 of estrous cycle. In this study, the birth weights and gestation lengths of half-sib single calves for bull A and B were analyzed.The numbers of single calves born by transfer of IVP and IVD embryos for bull A and B were 133 and 121, 243 and 465, respectively. The birth weight of the IVP calves was significantly higher (P<0.01) than that of the IVD (bull A: 31.0+/-0.4 kg versus 27.2+/-0.4 kg and bull B: 29.9+/-0.6 kg versus 26.6+/-0.2 kg). Gestation length of the IVP calves for bull A was significantly longer (P<0.01) than that of the IVD (291.9+/-0.9 days versus 283.6+/-0.5 days). However, for bull B, there were no differences in gestation length between the IVP and IVD calves (285.9+/-0.7 days versus 286.2+/-0.3 days). These results clearly indicated that IVP calves had heavier birth weights than IVD calves but that the average gestation length of IVP calves was not always longer than that of IVD calves. Furthermore, the birth rate of heavier calves and the incidence of stillbirth and perinatal mortality up to 48 h post partum in IVP calves (bull A: 11.3%, bull B: 7.8%) were greater (P<0.05) than those in IVD calves from both bulls (bull A: 4.1%, bull B: 3.7%). 相似文献
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