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排序方式: 共有1153条查询结果,搜索用时 218 毫秒
51.
Hsp70 family member, mot-2/mthsp70/GRP75, binds to the cytoplasmic sequestration domain of the p53 protein 总被引:12,自引:0,他引:12
Wadhwa R Yaguchi T Hasan MK Mitsui Y Reddel RR Kaul SC 《Experimental cell research》2002,274(2):246-253
Hsp70 family member mot-2/mthsp70/GRP75/PBP74 was shown to bind to the tumor suppressor protein p53. In this study, by in vivo coimmunoprecipitation of mot-2 with p53 and its deletion mutants, the mot-2 binding site of p53 was mapped to its C-terminal amino acid residues 312-352, a region of p53 that includes its cytoplasmic sequestration domain. These data demonstrate that cytoplasmic sequestration and inactivation of p53 by mot-2 occurs by its binding to the cytoplasmic sequestration domain. Therefore, perturbation of mot-p53 interactions can be employed to abrogate cytoplasmic retention of wild-type p53 in tumors. 相似文献
52.
Sugishima M Sakamoto H Kakuta Y Omata Y Hayashi S Noguchi M Fukuyama K 《Biochemistry》2002,41(23):7293-7300
Heme oxygenase (HO) catalyzes the oxidative cleavage of heme to biliverdin by utilizing O(2) and NADPH. HO (apoHO) was crystallized as twinned P3(2) with three molecules per asymmetric unit, and its crystal structure was determined at 2.55 A resolution. Structural comparison of apoHO and its complex with heme (HO-heme) showed three distinct differences. First, the A helix of the eight alpha-helices (A-H) in HO-heme, which includes the proximal ligand of heme (His25), is invisible in apoHO. In addition, the B helix, a portion of which builds the heme pocket, is shifted toward the heme pocket in apoHO. Second, Gln38 is shifted toward the position where the alpha-meso carbon of heme is located in HO-heme. Nepsilon of Gln38 is hydrogen-bonded to the carbonyl group of Glu29 located at the C-terminal side of the A helix in HO-heme, indicative that this hydrogen bond restrains the angle between the A and B helices in HO-heme. Third, the amide group of Gly143 in the F helix is directed outward from the heme pocket in apoHO, whereas it is directed toward the distal ligand of heme in HO-heme. This means that the F helix around Gly143 must change its conformation to accommodate heme binding. The apoHO structure has the characteristic that the helix on one side of the heme pocket fluctuates, whereas the rest of the structure is similar to that of HO-heme, as observed in such hemoproteins as myoglobin and cytochromes b(5) and b(562). These structural features of apoHO suggest that the orientation of the proximal helix and the position of His25 are fixed upon heme binding. 相似文献
53.
Arai K Toh S Tsubo K Nishikawa S Narita S Miura H 《Plastic and reconstructive surgery》2002,109(7):2301-2306
The clinical results and complications of the vascularized fibular graft for the reconstruction of various long bone defects were reviewed in 60 cases. Bony reconstruction was achieved in 57 of the 60 cases; however, various postoperative complications occurred in 54 percent of the cases. One case of arterial thrombosis of an anastomosed vessel and nine cases of venous congestion of the monitoring flap occurred in the early postoperative periods. The authors managed the nine cases of venous congestion of the flap conservatively, and all flaps survived. Partial necrosis of the flap was noted in eight of these nine cases, but additional surgical intervention was required in only four cases. Treatment included a gastrocnemius musculocutaneous flap in one case and a full-thickness skin graft in three cases. The vascularized fibula survived and bony fusion was achieved in all of these cases. The one case of arterial thrombosis resulted in graft failure due to a delay in the decision to perform a thrombectomy. Graft fracture occurred in 13 cases as the mechanical stress to the graft increased. In two cases of femoral reconstruction, graft fracture occurred during dynamization of the graft, despite the use of an Ilizarov external fixator. Correct alignment between the recipient bone and the external fixator is a prerequisite to preventing graft fracture. Vascularized fibular grafting offers the patient a great deal of benefit; however, this graft has a concomitant high risk of complications. Great attention to detail must be paid to prevent postoperative complications. 相似文献
54.
55.
Sakai T Michikawa H Furuyama S Sugiya H 《Comparative biochemistry and physiology. Part B, Biochemistry & molecular biology》2002,132(4):801-809
Guanosine 3′,5′-monophosphate (cGMP) is an intracellular messenger in various kinds of cell. We investigated the regulation of cGMP production by nitric oxide (NO) in rabbit submandibular gland cells. Methacholine, a muscarinic cholinergic agonist, stimulated cGMP production in a dose- and time-dependent manner, but the α-agonist phenylephrine, substance P and the β-agonist isoproterenol failed to evoke cGMP production. In fura-2-loaded cells, methacholine induced an increase in intracellular Ca2+ ([Ca2+]i) in a concentration-dependent manner, which was similar to that for cGMP production. When the external Ca2+ was chelated with EGTA, methacholine failed to induce cGMP production. Ca2+ ionophore A23187 and thapsigargin, which induce the increase in [Ca2+]i without activation of Ca2+-mobilizing receptors, mimicked the effect of methacholine. cGMP production induced by methacholine, A23187 and thapsigargin was clearly inhibited by NG-nitro-
-arginine methylester (L-NAME), a specific inhibitor of nitric oxide synthase (NOS). S-Nitroso-N-acetyl-
-penicillamine (SNAP), a NO donor, induced cGMP formation. In the lysate of rabbit submandibular gland cells, Ca2+-regulated nitric oxide synthase activity was detected. These findings suggest that cGMP production induced by the activation of muscarinic cholinergic receptors is regulated by NO generation via the increase in [Ca2+]i. 相似文献
56.
The phase-resetting experiment was applied to human periodic finger tapping to understand how its rhythm is controlled by
the internal neural clock that is assumed to exist. In the experiment, the right periodic tapping movement was disturbed transiently
by a series of left finger taps in response to impulsive auditory cues presented randomly at various phases within the tapping
cycle. After each left finger tap, the original periodic tapping was reestablished within several tapping cycles. Influences
of the disturbance on the periodic right finger tapping varied depending on the phase of the periodic right finger tapping
at which each left finger tap was made. It was confirmed that the periodic tapping was disturbed not by the auditory cues
but by the left finger taps. Based on this fact, in this paper each single left tap was considered as the stimulus, and the
phase of the periodic tapping of the right index finger when the left tap was executed as the phase of the stimulus. Responses
of the neural activities (magnetoencephalography, MEG), the tapping movement, and the corresponding muscle activities (electromyography)
were simultaneously measured. Phase-resetting curves (PRCs) representing the degree of phase reset as a function of the phase
of the stimulus were obtained both for the left sensorimotor cortex MEG response and for the right index finger tapping response.
The shapes of both PRCs were similar, suggesting that the phase reset of the left sensorimotor cortex activities and that
of the finger tapping rhythm were the same. Four out of eight subjects showed type-0 reset in Winfree's definition, and the
others showed type-1 reset. For general limit-cycle oscillators, type-0 reset is obtained for relatively strong perturbations
and type 1 for weak perturbations. It was shown that the transient response of MEG to the single left tap stimuli in type-0
subjects, where the phase was progressively reset, were different from those in type-1 subjects. Based on detailed analysis
of the differences, a neural network model for the phase reset of the tapping rhythm is proposed.
Received: 10 February 2000 / Accepted in revised form: 15 January 2002 相似文献
57.
Ogata Y Nakao S Shimizu E Matsuda-Honjyo Y Yamazaki M Furuyama S Sugiya H 《Cell biology international》2003,27(8):689-693
Bradykinin (1 microM) and histamine (100 microM) evoked an initial transient increase and a subsequent sustained increase in intracellular Ca(2+) concentration ([Ca(2+)](i)) in fura-2-loaded human gingival fibroblasts, which may be attributed to Ca(2+) release from intracellular stores and Ca(2+) entry from extracellular sites, respectively. In fibroblasts pretreated with tyrosine kinase inhibitors such as herbimycin A (1 microM) and tyrphostin 47 (20 microM), the sustained level of [Ca(2+)](i) induced by bradykinin and histamine increased, but not the initial peak level. In the absence of external Ca(2+), bradykinin and histamine induced only the transient increase in [Ca(2+)](i), but a subsequent addition of Ca(2+) to the medium resulted in a sustained increase in [Ca(2+)](i) caused by Ca(2+)entry. Thapsigargin, an inhibitor of Ca(2+)-ATPase in inositol 1,4,5-trisphosphate-sensitive Ca(2+) stores, mimicked the effect of bradykinin and histamine. In the fibroblasts pretreated with tyrosine kinase inhibitors, the bradykinin-, histamine- and thapsigargin-induced Ca(2+) entry was clearly enhanced, but not the transient [Ca(2+)](i) increase. Tyrosine phosphatase inhibitor benzylphosphonic acid (200 microM) had no effect on Ca(2+)entry or transient [Ca(2+)](i) increase. These results suggest that tyrosine phosphorylation is involved in Ca(2+) entry in human gingival fibroblasts. 相似文献
58.
-A new species of anisogammarid amphipod, Jesogammarus (Jesogammarus) mikadoi sp. nov., is described from freshwater habitats in northern Honshu, Japan. The species is distinguished from its congeners by having dorsal setae on pereonites 5-7 and pleonites 1-3. 相似文献
59.
Toshima G Kawamura S Araki T Torikata T 《Bioscience, biotechnology, and biochemistry》2003,67(3):540-546
The courses of the reaction catalyzed by guinea hen egg-white lysozyme (GHL), in which Asn113 and Arg114 at subsites E and F in hen egg-white lysozyme (HEL) are replaced by Lys and His, respectively, was studied with the substrate N-acetylglucosamine pentamer, (GlcNAc)5. Although GHL was found to retain the main-chain folding similar to HEL as judged from CD spectroscopy, the courses of GHL showed increased production of (GlcNAc)4 and reduced production of (GlcNAc)2 when compared with HEL. To identify critical residue(s) involved in the alteration in the courses of GHL, two mutant enzymes as to subsites E and F in HEL, N113K and R114H, were prepared by site-directed mutagenesis. Kinetic analysis of these mutants revealed that the mutation of Asn113 to Lys had little effect on the courses of HEL, while the Arg114 to His mutation completely reproduced the courses of GHL, demonstrating that His114 in GHL is the key residue responsible for the characteristic courses of GHL. Computer simulation of the reaction courses of the R114H mutant revealed that this substitution decreased not only the binding free energies for subsites E and F, but also the rate constant of transglycosylation. The Arg residue at position 114 may play an important role in the transglycosylation activity of HEL. 相似文献
60.