• 한국발생생물학회지:발생과생식
• /
• 제15권1호
• /
• pp.31-39
• /
• 2011

Change in intracellular $Ca^{2+}$-concentration ($[Ca^{2+}]_i$) is an essential event for egg activation and further development. $Ca^{2+}$ ion is originated from intracellular $Ca^{2+}$-store via inositol 1,4,5-triphosphate receptor and/or $Ca^{2+}$ influx via $Ca^{2+}$ channel. This study was performed to investigate whether changes in $Ca^{2+}$/calmodulin dependent protein kinase II (CaM KII) activity affect $Ca^{2+}$ influx during artificial egg activation with ethanol using $Ca^{2+}$ monitoring system and whole-cell patch clamp technique. Under $Ca^{2+}$ ion-omitted condition, $Ca^{2+}$-oscillation was stopped within 30 min post microinjection of porcine sperm factor, and ethanol-induced $Ca^{2+}$ increase was reduced. To investigate the role of CaM KII known as an integrator of $Ca^{2+}$- oscillation during mammalian egg fertilization, CaM KII activity was tested with a specific inhibitor KN-93. In the eggs treated with KN-93, ethanol failed to induce egg activation. In addition, KN-93 inhibited inward $Ca^{2+}$ current ($I_{Ca}$) in a time-dependent manner in whole-cell configuration. Immunostaining data showed that the voltage-dependent $Ca^{2+}$ channels were distributed along the plasma membrane of mouse egg and 2-cell embryo. From these results, we suggest that $Ca^{2+}$ influx during fertilization might be controlled by CaM KII activity.

• 생명과학회지
• /
• 제21권5호
• /
• pp.671-677
• /
• 2011

대두의 세포막에 존재하는 SCA1은 칼모듈린에 의해서 조절된다는 내용을 이전에 보고하였다. 본 연구에서는 대두의 $Ca^{2+}$-ATPase인 SCA2에 관한 특성을 연구하였다. SCA2는 SCA1과 아미노산 서열 비교에서 78%로 높은 유사성을 나타내며, 10개의 transmembrane 도메인이 존재하는 것을 확인하였다. CaM overaly assay로부터, SCA2는 칼슘에 의존적인 방법으로 칼모듈린과 결합한다는 것을 보여주었으며, Southern blot 분석 결과, 대두의 genome에는 두 종류의 $Ca^{2+}$-ATPase가 존재하는 것으로 보인다. SCA2의 $Ca^{2+}$-ATPase 효소활성을 확인하고자 yeast mutant를 이용하여 complementation assay를 수행해 보면, SCA2가 $Ca^{2+}$-ATPase의 효소활성을 가지는 것을 보여 주었다. 이러한 결과들은 SCA2가 식물에 존재하는 type IIB $Ca^{2+}$-ATPase들과 구조적으로 높은 유사성을 가진다는 것을 시사한다.

• 약학회지
• /
• 제43권5호
• /
• pp.659-664
• /
• 1999

To investigate the difference of contractile mechanism between KCI and phenylephrine-induced contraction, we observed effects of $Ca^{2+}$ antagonists and protein kinase inhibitors on aorta contraction of rats. Verapamil dose-dependently inhibited the contraction induced by KCI and phenylephrine, the inhibitory effect of verapamil was more potent in KCI-induced contraction than phenylephrine-induced contraction. Econazole and TMB-8 significantly inhibited CKI-induced contraction but did not inhibit phenylephrine-induced contraction. Staurosporine dose-dependently inhibited both KCI and phenylephrine-induced contraction. Genistein and calmodulin antagonists (W-7 and trifluoperazine) also inhibited both contraction in a dose dependent manner. However, the inhibitory effects of genistein and calmodulin antagonists were more potent in phenylephrine-induced contraction than KCI-induced contraction. These results suggest that involvements of $Ca^{2+}$ channel and protein kinase in rat aorta contraction were dependent on agonist causing aorta smooth muscle contraction.

• The Korean Journal of Physiology and Pharmacology
• /
• 제23권3호
• /
• pp.219-227
• /
• 2019

Polycystic kidney disease 2-like-1 (PKD2L1), polycystin-L or transient receptor potential polycystin 3 (TRPP3) is a TRP superfamily member. It is a calcium-permeable non-selective cation channel that regulates intracellular calcium concentration and thereby calcium signaling. Although the calmodulin (CaM) inhibitor, calmidazolium, is an activator of the PKD2L1 channel, the activating mechanism remains unclear. The purpose of this study is to clarify whether CaM takes part in the regulation of the PKD2L1 channel, and if so, how. With patch clamp techniques, we observed the current amplitudes of PKD2L1 significantly reduced when co-expressed with CaM and $CaM{\triangle}N$. This result suggests that the N-lobe of CaM carries a more crucial role in regulating PKD2L1 and guides us into our next question on the different functions of two lobes of CaM. We also identified the predicted CaM binding site, and generated deletion and truncation mutants. The mutants showed significant reduction in currents losing PKD2L1 current-voltage curve, suggesting that the C-terminal region from 590 to 600 is crucial for maintaining the functionality of the PKD2L1 channel. With PKD2L1608Stop mutant showing increased current amplitudes, we further examined the functional importance of EF-hand domain. Along with co-expression of CaM, ${\triangle}EF$-hand mutant also showed significant changes in current amplitudes and potentiation time. Our findings suggest that there is a constitutive inhibition of EF-hand and binding of CaM C-lobe on the channel in low calcium concentration. At higher calcium concentration, calcium ions occupy the N-lobe as well as the EF-hand domain, allowing the two to compete to bind to the channel.

• 분석과학
• /
• 제24권6호
• /
• pp.527-532
• /
• 2011

IQGAP1은 세포 내에서 암세포화, 세포이동과 같은 다양한 기능을 수행하고 있으며, $Ca^{2+}$-비의존성 calmodulin (CaM) 결합 단백질로 잘 알려져 있다. IQGAP1내에는 IQ부위가 4 번 반복해서 나타나는데, 이 부위가 IQGAP1의 CaM 결합에 중요한 역할을 한다고 알려져 있다. 이전의 연구를 통해 4개의 IQ 부위 모두 $Ca^{2+}$/CaM과의 결합에 관여하고, IQ3와 IQ4는 $Ca^{2+}$이 결합되지 않는 상태의 CaM인 proCaM 결합에 관여 한다고 알려져 있다. 그러나, 이러한 각각의 IQ 부위와의 결합성이 CaM과 직접적인 결합인지, 아니면 다른 단백질이 매개하는 간접적인 결합인지 알려져 있지 않았다. 따라서, 본 연구에서는 IQGAP1의 각각의 IQ 부위와 CaM의 결합성을 직접적으로 알아보기 의해 in vitro에서 조사해 보았다. 그 결과, 흥미롭게도 이전의 결과와는 다르게 4개의 IQ 부위 중에서 IQ3는 의미있는 $Ca^{2+}$-비의존성 CaM결합성이 있음을 알게 되었고, IQ1는 약한 $Ca^{2+}$-의존성 CaM 결합성이 있음을 알게 되었다. 반면에, 다른 IQ 부위들은 CaM과의 결합력이 약하거나 없음을 확인하였다. 또한, 기존의 IQ 부위 이외에 IQ(2.7-3)과 IQ(3.5-4.4) 부위가 의미있는 CaM 결합성이 있음을 확인하게 되었다. 따라서, 본 연구 결과 CaM이 IQGAP1을 기존의 보고와는 다른 방식으로 조절할 수 있을 가능성이 있음을 알게 되었고, 새로운 결합 부위 동정을 통해 IQGAP1과 CaM의 결합이 미치는 생리학적인 의미를 연구할 수 있는 토대를 마련하였다.

• Plant Biotechnology Reports
• /
• 제5권3호
• /
• pp.225-234
• /
• 2011

Arabidopsis mutants with T-DNA insertion in seven calmodulin genes (CAM) were used to determine the specific role of CAM in the tolerance of plants to oxidative stress induced by paraquat and hydrogen peroxide ($H_2O_2$) treatments. Arabidopsis calmodulin mutants (cam) were screened for seedling growth, seed germination, induced oxidative damage, and levels of ${\gamma}$-aminobutyric acid (GABA) shunt metabolites. Only the cam5-4 and cam6-1 mutants exhibited an increased sensitivity to paraquat and $H_2O_2$ during seed germination and seedling growth. In response to treatments with $3{\mu}M$ paraquat and 1 mM $H_2O_2$, only the cam5-4, cam6-1 mutants showed significant changes in malonaldehyde (MDA) levels in root and shoot tissues, with highly increased levels of MDA. In terms of the GABA shunt metabolites, GABA was significantly elevated in root and shoot tissues in response to the paraquat treatments in comparison to alanine and glutamate, while the levels of all shunt metabolites increased in root tissue but not in the shoot tissue following the $H_2O_2$ treatments. GABA, alanine and glutamate levels were significantly increased in root and shoot of the cam1, cam4, cam5-4, and cam6-1 mutants in response to paraquat (0.5, 1 and $3{\mu}M$), while they were increased only in the root tissue of the cam1, cam4, cam5-4, and cam6-1 mutants in response to $H_2O_2$ (200 and $500{\mu}M$, 1 mM). These data show that the cam5-4 and cam6-1 mutants were sensitive to the induced oxidative stress treatments in terms of seed germination, seedling growth, and oxidative damage. The accumulation of GABA shunt metabolites as a consequence of the induced oxidative stress treatments (paraquat and $H_2O_2$ treatments) suggests that the GABA shunt pathway and the accumulation of GABA metabolites may contribute in antioxidant machinery associated with reactive oxygen species and in the acquisition of tolerance in response to induced oxidative stress in Arabidopsis seedlings.

• Archives of Pharmacal Research
• /
• 제29권8호
• /
• pp.657-665
• /
• 2006

We recently reported that dimethylsphingosine (DMS), a metabolite of sphingolipids, increased intracellular pH and $Ca^{2+}$ concentration in U937 human monocytes. In the present study, we found that dimethylphytosphingosine (DMPH) induced the above responses more robustly than DMS. However, phytosphingosine, monomethylphytosphingosine or trimethylsphingosine showed little or no activity. Synthetic C3 deoxy analogues of sphingosine did show similar activities, with the C16 analogue more so than C18. The following structure-activity relationships were observed between DMS derivatives and the intracellular pH and $Ca^{2+}$ concentrations in U937 monocytes; 1) dimethyl modification is important for the DMS-induced increase of intracellular pH and $Ca^{2+}$, 2) the addition of an OH group on C4 enhances both activities, 3) the deletion of the OH group on C3 has a negligible effect on the activities, and 4) C16 appears to be more effective than C18. We also found that W-7, a calmodulin inhibitor, blocked the DMS-induced pH increase, whereas, KN-62, ML9, and MMPX, specific inhibitors for calmodulin-dependent kinase II, myosin light chain kinase, and $Ca^{2+}$-calmodulin-dependent phosphodiesterase, respectively, did not affect DMS-induced increases of pH in the U937 monocytes.

• Journal of Ginseng Research
• /
• 제33권1호
• /
• pp.59-64
• /
• 2009

$Ca^{2+}$ and calmodulin (CaM), a key $Ca^{2+}$ sensor in all eukaryotes, have been implicated for defense responses of plants. Eukaryotic CaM contains four structurally and functionally similar $Ca^{2+}$ domains named I, II, III and IV. Each $Ca^{2+}$ binding loop consists of 12 amino acid residues with ligands arranged spatially to satisfy the octahedral symmetry of $Ca^{2+}$ binding. To investigate the altered gene expression and the role of CaM in ginseng plant defense system, cDNA clone containing a CaM gene, designated PgCaM was isolated and sequenced from Panax ginseng. PgCaM, which has open reading frame of 450 nucleotides predicted to encode a precursor protein of 150 amino acid residues. Its sequence shows high homologies with a number of other CaMs, with more similarity to CaM of Daucus carota (AAQ63461). The expression of PgCaM in different P. ginseng organs was analyzed using real time PCR. The results showed that PgCaM expressed at different levels in young leaves, shoots, and roots of 3-week-old P. ginseng. In addition, the expressions of PgCaM under different abiotic stresses were analyzed at different time intervals.

• Journal of Yeungnam Medical Science
• /
• 제13권1호
• /
• pp.46-58
• /
• 1996

세포막 정보전달 과정에 참여하는 효소로 inositol triphosphate($InsP_3$)를 분해하는 $InsP_3$ kinase를 소의 뇌 조직으로 부터 새로운 정제방법을 개발하고 isozyme들의 특성을 관찰하여 다음과 같은 결과를 얻었다. 분쇄한 소의 뇌조직을 PEG로 단백침전하고 DEAE cellulose chromatography 하여 $InsP_3$ kinase I, II의 두 isozyme을 얻었으며, 각각의 isozyme 분획을 Matrix green gel 및 calmodulin-Affigel 15 column으로 chromatography하였다. Phenyl-TSK HPLC하여 정제하였으며 I은 3,103배, II는 2,310 배의 정제를 나타내었다. 정제 단계에서 specific activity를 비교해 볼 때 Matrix green gel chromatography가 DEAE cellulose에서 보다 I이 30배, II가 약 2.3배로 나타났고 정제배수도 I이 17.2%에서 62.1%로 II가 16.6%에서 38%로 나왔으나 calmodulin-Affigel 15과 비교시는 큰 차이가 없었다. 그러므로 Matrix green gel이 정제에서 매우 중요한 단계라 할 수 있다. 효소의 분자량을 알기 위하여 DEAE HPLC로 두 개의 isozyme을 분리하여 전기영동한 결과 I은 환자량 145,000, 85,500 및 69,500이 3개의 단백질을 얻었고 II는 분자량 79,000 및 57,000의 2개의 단백질을 얻었다.

• 분석과학
• /
• 제25권5호
• /
• pp.333-338
• /
• 2012

IQGAPs는 세포 내에서 암세포화, 세포이동, 세포분열과 같은 다양한 기능을 수행하고 있으며, 대표적인 calmodulin (CaM) 결합 단백질로, human의 경우 3 개의 isoform이 알려지고 있다. IQGAPs는 각각 네 개의 IQ 부위를 가지고 있으며, 이들이 CaM과의 결합에 관여한다고 보고되고 있으나, 현재까지 IQGAP1에 비해 IQGAP3에서는 각각의 IQ 부위가 가지는 CaM 결합 특성에 대해선 연구가 미비한 실정이다. 따라서, 본 연구에서는 IQGAP3 내의 IQ 부위들과 CaM과의 결합성을 연구하였다. 이러한 연구를 수행한 결과, 네 개의 IQ부위가 의미 없는 CaM 결합성을 가지는 IQGAP1과는 다르게, IQGAP3는 IQ2와 IQ3가 $Ca^{2+}$-비의존성 CaM 결합을 보이고, IQ1과 IQ4는 결합성이 없음을 알 수 있었다. 또한, IQGAP1에서 새롭게 알려진 $Ca^{2+}$-의존성 CaM 결합 부위인 IQ(3.5-4.4) 부위가, IQGAP3에서도 잘 보존되어 있음을 알 수 있었다. 본 연구를 통해 IQGAP3의 IQ부위는 IQGAP1와는 다른 CaM 결합성이 있음을 알게 되었다. 이러한 결과는 각각의 IQGAP isoform들이 각기 다른 CaM 결합성으로 세포 내에서 다른 생리작용을 수행할 가능이 있음을 제시한다.