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INTRODUCTIONCiliaryneurotrophicfactor (CNTF)isanat urallyoccurringproteinwithamolecularmassofapproximately 2 2kDa .Itisexpressedinglialcellswithinthecentralandperipheralnervoussystems.CNTFstimulatesgeneexpression ,cellsurvivalordifferentiationinavarietyof… 相似文献
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Ciliary neurotrophic factor (CNTF) has pleiotropic actions on many neuronal populations as well as on glia. Signal transduction
by CNTF requires that it bind first to CNTF-R, permitting the recruitment of gp130 and LIF-R, forming a tripartite receptor
complex. Cells that only express gp130 and LIF-R, but not CNTF-R are refractory to stimulation by CNTF. On many target cells
CNTF only acts in the presence of its specific agonistic soluble receptors. We engineered a soluble fusion protein by linking
the COOH-terminus of sCNTF-R to the NH2-terminus of CNTF. Recombinant CNTF/sCNTF-R fusion protein (Hyper-CNTF) was successfully expressed in COS-7 cells. The apparent
molecular mass of the Hyper-CNTF protein was estimated from western blots to be 75 kDa. Proliferation assays of transfected
BAF/3 cells in response to CNTF and Hyper-CNTF were used to verify the activity of the cytokines. The proliferative results
confirmed that CNTF required homodimerization of the gp130, CNTF-R and LIF-R receptor subunit whereas Hyper-CNTF required
heterodimerization of the gp130 and LIF-R receptor subunit. We concluded that the fusion protein Hyper-CNTF had superagonistic
activity on target cells expressing gp130 and LIF-R, but lacking membrane-bound CNTF-R.
Project supported by the Scientific Research Foundation for the Returned Overseas Chinese Scholar, Zhejiang Province, China
and SFB415, TP B5, Germany. 相似文献
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应用定量 X射线微区分析技术结合细胞化学技术 ,分析测定用单纯冷冻法保存离体猫肾脏过程中肾脏细胞的胞浆、线粒体、内质网、细胞核等细胞器内的 Ca2 浓度变化 ,并探索钙通道阻滞剂对这种变化的影响 .保存 36h及 72 h后 ,线粒体与胞浆中 Ca的峰背比极显著地提高 ,内质网、细胞核中 Ca颗粒减少 .添加 Verapamil后 ,保存过程中细胞器内 Ca2 无显著变化 .线粒体中的Ca峰背比与胞浆中的呈强的正相关 ,r=0 .990 .实验结果揭示 :保存过程中 ,Ca2 由 Ca库 (内质网等 )进入胞浆中 ,线粒体在胞浆 Ca2 浓度高时摄取 Ca2 ,而钙通道阻滞剂可抑制该过程 相似文献
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猫肾低温保存过程中近曲小管超微结构变化 总被引：1，自引：0，他引：1
肾脏器官在低温离体保存过程中，血管内皮细胞和肾小管上皮细胞功能结构的完整性是维持器官功能的关键。近曲小管是肾脏完成肾小球滤过液重吸收过程最主要的功能结构区域。因其细胞结构特点，在低温保存过程中近曲小管上皮细胞对外环境发生变化最敏感。本文选取离体低温保存了0，24，48和72h的能皮质样品，利用透射电子显微镜切片观察其近曲小管超微结构，以了解肾脏在离体存活过程中导致肾脏功能衰退的近曲小管结构动态变化过程。结果显示了在低温保存的过程中，近曲小管刷状缘结构脱落在小管腔内重新聚集成囊状结构，阻塞肾小管，导致肾脏重吸收功能破坏。 相似文献
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