• Bulletin of the Korean Chemical Society
• /
• 제32권6호
• /
• pp.2135-2136
• /
• 2011

• Bulletin of the Korean Chemical Society
• /
• 제32권12호
• /
• pp.4435-4437
• /
• 2011

• Bulletin of the Korean Chemical Society
• /
• 제33권1호
• /
• pp.275-277
• /
• 2012

• Bulletin of the Korean Chemical Society
• /
• 제30권5호
• /
• pp.1190-1192
• /
• 2009

• Bulletin of the Korean Chemical Society
• /
• 제30권8호
• /
• pp.1858-1860
• /
• 2009

• Bulletin of the Korean Chemical Society
• /
• 제25권12호
• /
• pp.1755-1756
• /
• 2004

• Journal of Microbiology and Biotechnology
• /
• 제18권2호
• /
• pp.365-368
• /
• 2008

Calcium entry through $Ca_v3.2Ca^{2+}$ channels plays essential roles for various physiological events including thalamic oscillation, muscle contraction, hormone secretion, and sperm acrosomal reaction. In this study, we examined how protein tyrosine phosphatases or protein tyrosine kinases affect $Ca_v3.2Ca^{2+}$ channels reconstituted in Xenopus oocytes. We found that $Ca_v3.2$ channel activity was reduced by 25% in response to phenylarsine oxide (tyrosine phosphatase inhibitor), whereas it was augmented by 19% in response to Tyr A47 or herbimycin A (tyrosine kinase inhibitors). However, other biophysical properties of $Ca_v3.2$ currents were not significantly changed by the drugs. These results imply that $Ca_v3.2$ channel activity is capable of being increased by activation of tyrosine phosphatases, but is decreased by activation of tyrosine kinases.

• Bulletin of the Korean Chemical Society
• /
• 제32권7호
• /
• pp.2167-2168
• /
• 2011

• Journal of Korean Neurosurgical Society
• /
• 제46권4호
• /
• pp.389-396
• /
• 2009

Objective : Triptolide (TP) has been reported to suppress the expression of mitogen-activated protein kinase (MAPK) phosphatase-1 (MKP-1), of which main function is to inactivate the extracellular signal-regulated kinase-1/2 (ERK-1/2), the p38 MAPK and the c-Jun N-terminal kinase-1/2 (JNK-1/2), and to exert antiproliferative and pro-apoptotic activities. However, the mechanisms underlying antiproliferative and pro-apoptotic activities of TP are not fully understood. The purpose of this study was to examine whether the down-regulation of MKP-1 expression by TP would account for antiproliferative activity of TP in immortalized HT22 hippocampal cells. Methods : MKP-1 expression and MAPK phosphorylation were analyzed by Western blot. Cell proliferation was assessed by $^3H$-thymidine incorporation. Small interfering RNA (siRNA) against MKP-1, vanadate (a phosphatase inhibitor), U0126 (a specific inhibitor for ERK-1/2), SB203580 (a specific inhibitor for p38 MAPK), and SP600125 (a specific inhibitor for JNK-1/2) were employed to evaluate a possible mechanism of antiproliferative action of TP. Results : At its non-cytotoxic dose, TP suppressed MKP-1 expression, reduced cell growth, and induced persistent ERK-1/2 activation. Similar growth inhibition and ERK-1/2 activation were observed when MKP-1 expression was blocked by MKP-1 siRNA and its activity was inhibited by vanadate. The antiproliferative effects of TP, MKP-1 siRNA, and vanadate were significantly abolished by U0126, but not by SB203580 or SP600125. Conclusion : Our findings suggest that TP inhibits the growth of immortalized HT22 hippocampal cells via persistent ERK-1/2 activation by suppressing MKP-1 expression. Additionally, this study provides evidence supporting that MKP-1 may play an important role in regulation of neuronal cell growth.

• Parasites, Hosts and Diseases
• /
• 제31권4호
• /
• pp.353-362
• /
• 1993

Fibricola seoulensis의 성체와 피낭유충에서 acid(Acpase)와 alkaline phosphatase (AIPase)의 분포와 동위효소유형 (유형)의 변화를 추구하고자 효소조직화학적 방법과 전기영동법을 이용하여 성체에서 Acpase는 pH 5가 최적의 활성이 나타났고. 분자량이 95 kDa. 85 kDa. 73 kDa. 62 kDa인 4종류의 동위효소가 동정되었다. 피낭유충에서 A쳬ase는 활성이 약하거나 나타나지 않았고. 분자량이 62 kDa인 1종류의 동위효소가 동정되었다 성체와 피낭유충에 AIPase는 pH 8에서 최적의 활성이 나타났고, 피낭유충의 생식원기에서 강한 활성이 나타났다.