18 research outputs found
KHDC1B Is a Novel CPEB Binding Partner Specifically Expressed in Mouse Oocytes and Early Embryos
The expression and activities of two members of a novel KH domain protein family were tested. KHDC1A and 1B are highly expressed in oocytes. Based on ectopic expression, KHDC1A regulates apoptosis whereas 1B interacts with the cytoplasmic polyadenylation machinery. KHDC1B may serve as a translational repressor during oocyte maturation
Chloroform Extract of Artemisia annua
Artemisia annua L. belongs to the Asteraceae family, which is indigenous to China. It has valuable pharmacological properties, such as antimalarial, anti-inflammatory, and anticancer properties. However, whether it possesses antiasthma properties is unknown. In the current study, chloroform extract of Artemisia annua L. (CEAA) was prepared, and we found that CEAA completely eliminated acetylcholine (ACh) or high K+-elicited (80 mM) contractions of mouse tracheal rings (TRs). Patch-clamp technique and ion channel blockers were employed to explore the underlying mechanisms of the relaxant effect of CEAA. In whole-cell current recording, CEAA almost fully abolished voltage-dependent Ca2+ channel (VDCC) currents and markedly enhanced large conductance Ca2+-activated K+ (BK) channel currents on airway smooth muscle cells (ASMCs). In single channel current recording, CEAA increased the opening probability but had no effect on the single channel conductance of BK channels. However, under paxilline-preincubated (a selective BK channel blocker) conditions, CEAA only slightly increased BK channel currents. These results indicate that CEAA may contain active components with potent antiasthma activity. The abolished VDCCs by CEAA may mainly contribute to the underlying mechanism through which it acts as an effective antiasthmatic compound, but the enhanced BK currents might play a less important role in the antiasthmatic effects
Deficiency of MTMR14 impairs male fertility in Mus musculus.
Calcium signalling is critical for successful fertilization. In spermatozoa, capacitation, hyperactivation of motility and acrosome reactions are all mediated by increases in intracellular Ca2+. Our previous reports have shown that deficiency of MTMR14, a novel phosphoinositide phosphatase, induces a muscle disorder by disrupting Ca2+ homeostasis. Recently, we found that MTMR14 is also expressed in the testes; however, whether deficiency of MTMR14 in the testes also alters the Ca2+ concentration and impairs male fertility remains entirely unknown. In the present study, we found that MTMR14 is also expressed in the testes and mature sperm cells, suggesting that deficiency of MTMR14 might have some effect on male fertility. Both in vivo fertility and in vitro fertilization tests were then performed, and we found that MTMR14-/- male mice showed decreased fertility. A series of experiments were then arranged to test the testis and sperm parameters; we found that MTMR14 deficiency caused small size of the testes, small numbers of both total and immotile sperm, expanded membrane of sperm tail, a decreased proportion of acrosome reaction, and in contrast, an increased proportion of abnormal sperm and augmented apoptosis, etc. Further study also found that the muscle force of the vas deferens decreased significantly in KO mice. Intracellular calcium homeostasis in the testes and epididymis was impaired by MTMR14 deletion; moreover, the relative mRNA expression levels of Itpr1, Itpr2, and Ryr3 were dramatically decreased in MTMR14 KO mice. Thus, MTMR14 deletion impairs male fertility by causing decreased muscle force of the vas deferens and intracellular calcium imbalance
Small kinetochore associated protein (SKAP) promotes UV-induced cell apoptosis through negatively regulating pre-mRNA processing factor 19 (Prp19).
Apoptosis is a regulated cellular suicide program that is critical for the development and maintenance of healthy tissues. Previous studies have shown that small kinetochore associated protein (SKAP) cooperates with kinetochore and mitotic spindle proteins to regulate mitosis. However, the role of SKAP in apoptosis has not been investigated. We have identified a new interaction involving SKAP, and we propose a mechanism through which SKAP regulates cell apoptosis. Our experiments demonstrate that both overexpression and knockdown of SKAP sensitize cells to UV-induced apoptosis. Further study has revealed that SKAP interacts with Pre-mRNA processing Factor 19 (Prp19). We find that UV-induced apoptosis can be inhibited by ectopic expression of Prp19, whereas silencing Prp19 has the opposite effect. Additionally, SKAP negatively regulates the protein levels of Prp19, whereas Prp19 does not alter SKAP expression. Finally, rescue experiments demonstrate that the pro-apoptotic role of SKAP is executed through Prp19. Taken together, these findings suggest that SKAP promotes UV-induced cell apoptosis by negatively regulating the anti-apoptotic protein Prp19
Bartonella type IV secretion effector BepC induces stress fiber formation through activation of GEF-H1.
Bartonella T4SS effector BepC was reported to mediate internalization of big Bartonella aggregates into host cells by modulating F-actin polymerization. After that, BepC was indicated to induce host cell fragmentation, an interesting cell phenotype that is characterized by failure of rear-end retraction during cell migration, and subsequent dragging and fragmentation of cells. Here, we found that expression of BepC resulted in significant stress fiber formation and contractile cell morphology, which depended on combination of the N-terminus FIC (filamentation induced by c-AMP) domain and C-terminus BID (Bartonella intracellular delivery) domain of BepC. The FIC domain played a key role in BepC-induced stress fiber formation and cell fragmentation because deletion of FIC signature motif or mutation of two conserved amino acid residues abolished BepC-induced cell fragmentation. Immunoprecipitation confirmed the interaction of BepC with GEF-H1 (a microtubule-associated RhoA guanosine exchange factor), and siRNA-mediated depletion of GEF-H1 prevented BepC-induced stress fiber formation. Interaction with BepC caused the dissociation of GEF-H1 from microtubules and activation of RhoA to induce formation of stress fibers. The ROCK (Rho-associated protein kinase) inhibitor Y27632 completely blocked BepC effects on stress fiber formation and cell contractility. Moreover, stress fiber formation by BepC increased the stability of focal adhesions, which consequently impeded rear-edge detachment. Overall, our study revealed that BepC-induced stress fiber formation was achieved through the GEF-H1/RhoA/ROCK pathway
Prp19 suppresses UV-induced apoptosis in HeLa cells.
<p>(A) HeLa cells were transfected with pcDNA-Myc or pcDNA-Myc-Prp19 and treated with 40 J/m<sup>2</sup> UV irradiation. The cell lysates were analyzed by immunoblotting with the antibodies indicated. GAPDH was used as a loading control. (B) The knockdown efficiency of siRNAs targeting Prp19 was verified by immunoblot analysis. (C) HeLa cells were transfected with siRNA-NC or siRNA-Prp19 #3 and treated with 40 J/m<sup>2</sup> UV irradiation. The cell lysates were analyzed by immunoblotting with the antibodies indicated. GAPDH was used as a loading control.</p