多囊蛋白,钙离子信号转导与常染色体显性遗传性多囊肾病

多囊肾疾病是由多囊蛋白-1或-2失能导致的,其囊肿的发生涉及到上皮细胞的过度增殖、轻度的分化不良以及囊液的积聚。多囊蛋白-1和多囊蛋白-2构成多囊蛋白离子通道复合物,参与Ca^(2+)信号转导,该通道复合物的病变直接引起细胞内Ca^(2+)调节的失衡导致囊肿的形成。

TROP2通过内质网钙铁离子交换影响胃癌侵袭的分子机制

目的探讨人滋养层细胞表面糖蛋白2(TROP2)通过内质网钙铁离子交换影响胃癌侵袭的分子机制。方法构建TROP2与PLOD2过表达/敲减细胞株,WB、RT-qPCR检测TROP2、PLOD2、磷脂酰肌醇4,5-二磷酸(PIP2)、胶原蛋白I型(COL-I)、缺氧诱导因子-1α(HIF-1α)、蛋白激酶C(PKC)mRNA和蛋白的表达水平,ELISA法检测三磷酸肌醇受体(IP3R)含量,比色分析法检测Fe^(2+)和Ca^(2+)含量。结果随着TROP2的表达量的变化,PLOD2、PIP2、IP3等蛋白水平随之同步变化,在PLOD2的过表达和敲减模型中,无论PLOD2如何变化,TROP2、PIP2、IP3R、PKC并无明显变化,但COL-I、HIF-1α随着PLOD2的变化同步增减。在离子水平,内质网Ca^(2+)浓度与TROP2和PLOD2的表达量呈正相关,Fe^(2+)浓度与TROP2和PLOD2的表达量呈负相关。结论PLOD2上游受TROP2的钙离子信号转导通路“内质网Ca^(2+)-Fe^(2+)交换”调控,下游通过调控HIF1α和胶原纤维交联促进肿瘤的侵袭、转移。

盐碱胁迫下植物生理和钙信号通路分子机制的研究进展

土壤的盐化和碱化往往伴随发生,在盐碱胁迫下,植物会遭受许多类型的非生物胁迫,严重影响植物的正常生长发育。本综述首先介绍了盐碱土的分类;其次从四个方面对植物在盐碱胁迫下体内产生相应生理机制进行详细介绍;接下来以植物在盐碱胁迫下产生的钙信号为重点进行阐述,包括植物首个非离子通道型盐胁迫下离子感受器GIPCs的发现、盐碱胁迫诱导的钙信号相关通道和转运蛋白、钙信号的感受与传递、以及其他与钙离子信号产生交叉的信号通路的研究进展。在碱胁迫中与钙信号的相关研究鲜有报道,本综述也介绍了此方面的最新研究。最后,对该研究领域目前需要解决的科学问题进行展望。

三磷酸肌醇受体在精卵结合过程中的作用

目前国内外均没有一种理想的男性避孕药物，安全有效的男性避孕药物开发也是生殖避孕领域的瓶颈之一。钙离子信号途径在精卵结合及早胚发育过程中发挥重要生理功能，而三磷酸肌醇（IP3）就是精子中参与钙离子信号转导的第二信使，通过与三磷酸肌醇受体（IP3R）结合，诱导钙离子的释放在精卵结合及早胚发育过程中发挥重要作用。

钙离子对内质网胁迫的影响

植物在遭受到恶劣环境后,不能通过移动来解除损伤,因而自身在长期的进化过程中形成了一套防御机制。现如今的粮食产量低下,绝大部分是由于环境胁迫所造成的,因此要想提高产量需改善植物生长环境,避免植物遭到环境胁迫。研究表明,适宜浓度的钙离子信号在胁迫途径中能够增强信号的转导及时参与植物的生理调控,避免植物受到毒害;当植物在逆境时内质网会受到胁迫,若是不能及时地启动防御机制会导致生理发生紊乱,严重时将导致死亡。很多研究表明了钙离子在多种非生物胁迫中都有参与调控的实例,但在内质网胁迫中的研究还未见报道。因此,研究钙离子与内质网胁迫之间的关系对于植物在逆境育种中具有重要的生理意义。

Inositol 1,4,5-trisphosphate 3-kinases:functions and regulations

Inositol 1,4,5-trisphosphate 3-kinase (IP3 3-kinase/IP3K) plays an important role in signal transduction in animal cellsby phosphorylating inositol 1,4,5-trisphosphate (IP3) to inositol 1,3,4,5-tetrakisphosphate (IP4). Both IP3 and IP4 arecritical second messengers which regulate calcium (Ca2+) homeostasis. Mammalian IP3Ks are involved in many biologicalprocesses, including brain development, memory, learning and so on. It is widely reported that Ca2+ is a canonicalsecond messenger in higher plants. Therefore, plant IP3K should also play a crucial role in plant development. Recently,we reported the identification of plant IP3K gene (AtIpk2β/AtIP3K) from Arabidopsis thaliana and its characterization.Here, we summarize the molecular cloning, biochemical properties and biological functions of IP3Ks from animal, yeastand plant. This review also discusses potential functions of IP3Ks in signaling crosstalk, inositol phosphate metabolism,gene transcriptional control and so on.

Differential activation of mitogen-activated protein kinases by γ-irradi-ation in IEC-6 cells: Role of intracellular Ca^(2+)

Objective: To explore the effects of γ-irradiation on mitogen-activated protein kinases (MAPKs) and role of intracellular calcium in this event in intestinal epithelial cell line 6 (IEC-6 cells). Methods: After cultured rat IIEC-6 cells with or without the pretreatment of intracellular Ca2+ chelator were exposed to Y-ir-radiation of 6 Gy, the total and phosphorylated MAPKs in the cells were determined with Western blotting and apoptosis was examined with flow cytometry. Activities of Extracellular signal-regulated protein kinase (ERK) and p38 MAPK were determined by using immuoprecipitation followed by Western blotting. Results: In response to γ-irradiation, phosphorylation of ERK was not significantly observed, while the levels of phosphorylated c-Jun NH2-terminal kinase (JNK) and p38 MAPK were increased in 30 min and reached the peak 2 h after exposure to 6 Gy γ-irradiation, though the cell viability was significantly lowered 12 h. On the other hand, no obvious changes were seen in the total protein levels of ERK, JNK and p38 MAPK. Chelation of intracellular Ca2+ almost completely suppressed the JNK and p38 MAPK phosphorylation induced by γ-irradia-tion, but removal of external Ca2+ had no such effect. Activation of p38 MAPK, but not of ERK, was seen to have a correlation with γ-irradiation induced apoptosis. Conclusion: The results suggest that γ-irradiation is a potent activator for JNK and p38 MAPK, and Ca2+ mobilized from intracellular stores plays an important role in the activation of MAPKs and the induction of apoptosis in IEC-6 cells.