• BMB Reports
• /
• 제46권3호
• /
• pp.169-174
• /
• 2013

The human $B_{12}$ trafficking chaperone hCblC is well conserved in mammals and non-mammalian eukaryotes. However, the C-terminal ~40 amino acids of hCblC vary significantly and are predicted to be deleted by alternative splicing of the encoding gene. In this study, we examined the thermostability of the bovine CblC truncated at the C-terminal variable region (t-bCblC) and its regulation by glutathione. t-bCblC is highly thermolabile ($T_m={\sim}42^{\circ}C$) similar to the full-length protein (f-bCblC). However, t-bCblC is stabilized to a greater extent than f-bCblC by binding of reduced glutathione (GSH) with increased sensitivity to GSH. In addition, binding of oxidized glutathione (GSSG) destabilizes t-bCblC to a greater extent and with increased sensitivity as compared to f-bCblC. These results indicate that t-bCblC is a more sensitive form to be regulated by glutathione than the full-length form of the protein.

• Asian Pacific Journal of Cancer Prevention
• /
• 제14권2호
• /
• pp.1073-1075
• /
• 2013

Background: In normal cells, activated epidermal growth factor receptor (EGFR) molecules are subjected to ubiquitination-mediated proteasome degradation pathway by c-Cbl, an ubiquitin ligase that checks uncontrolled proliferation. Hence expression of wild type c-Cbl molecule is essential to keep this degradation machinery in a functional state. Loss of expression or function of c-Cbl may consequently lead to sustained activation of EGFR and promote carcinogenesis, loss of function mutations in the c-Cbl gene already being reported in lung and hematopoietic cancers. However, the genetic status of c-Cbl in oral squamous cell carcinoma (OSCC) is not known. Hence in the present study we investigated the genomic DNA isolated from OSCC tissue biopsy samples for mutations in the RING finger domain coding region of c-Cbl gene, which has also been reported to be most frequently mutated in other cancers. Materials and Methods: Total genomic DNA isolated from thirty two post surgical OSCC tissue samples were amplified using primers flanking the exon 8 of c-Cbl gene that codes for the RING finger domain. The PCR amplicons were then resolved in a 1.2% agarose gel, purified and subjected to direct sequencing to screen for mutations. Results: The sequencing data of the thirty two OSCC samples did not identify mutations in the RING finger domain coding region of c-Cbl gene. Conclusions: To the best of our knowledge, this is the first time that the genetic status of c-Cbl gene in OSCC samples has been investigated. The present data indicates that genetic alteration of RING finger domain coding region of c-Cbl gene is relatively infrequent in OSCC samples.

• BMB Reports
• /
• 제44권3호
• /
• pp.170-175
• /
• 2011

We identified a bovine $B_{12}$ trafficking chaperone bCblC in Bos taurus that showed 88% amino acid sequence identity with a human homologue. The protein bCblC was purified from E. coli by over-expression of the encoding gene. bCblC bound cyanocobalamin (CNCbl), methylcobalamin (MeCbl) and adenosylcobalamin (AdoCbl) in the base-off states and eliminated the upper axial ligands forming aquo/hydroxocobalamin ($OH_2$/OHCbl) under aerobic conditions. A transition of $OH_2$/OHCbl was induced upon binding to bCblC. Interestingly, bCblC-bound $OH_2$/OHCbl did not react with reduced glutathione (GSH), while the reaction of free$OH_2$/OHCbl with GSH resulted in the formation of glutathionylcobalamin (GSCbl) and glutathione disulfide (GSSG). Furthermore we found that bCblC eliminates the GSH ligand of GSCbl forming $OH_2$/OHCbl. The results demonstrated that bCblC is a $B_{12}$ trafficking chaperone that binds cobalamins and protects $OH_2$/OHCbl from GSH, which could be oxidized to GSSG by free $OH_2$/OHCbl.

• Molecules and Cells
• /
• 제42권12호
• /
• pp.840-849
• /
• 2019

The spatiotemporal mitotic processes are controlled qualitatively by phosphorylation and qualitatively by ubiquitination. Although the SKP1-CUL1-F-box protein (SCF) complex and the anaphase-promoting complex/cyclosome (APC/C) mainly mediate ubiquitin-dependent proteolysis of mitotic regulators, the E3 ligase for a large portion of mitotic proteins has yet to be identified. Here, we report c-Cbl as an E3 ligase that degrades DDA3, a protein involved in spindle dynamics. Depletion of c-Cbl led to increased DDA3 protein levels, resulting in increased recruitment of Kif2a to the mitotic spindle, a concomitant reduction in spindle formation, and chromosome alignment defects. Furthermore, c-Cbl depletion induced centrosome over-duplication and centriole amplification. Therefore, we concluded that c-Cbl controls spindle dynamics and centriole duplication through its E3 ligase activity against DDA3.

• 대한원격탐사학회지
• /
• 제17권1호
• /
• pp.1-14
• /
• 2001

굴절 지수 구조 매개 변수(refractive index structure parameter) $C_n^2$의 증가는 보통 가온위(virtual potential temperature) ${\theta}_v$와 혼합비(mixing ratio) q의 연직 기울기가 최대가 되는 고도에서 발생하며, 대류 경계층(convective boundary layer)의 고도를 추정하는데 있어서 매우 유용한 매개 변수로 사용된다. 이 연구에서는 대류 경계층 고도의 추정에 이용되는 $C_n^2$ 첨두의 발생 특성이 조사되었으며, 또한 UHF 레이더로 관측된 $C_n^2$와 연직 속도의 분산 ${\sigma}_w$ 자료를 이용하여 대류 경계층 고도를 객관적으로 추정하는 방법이 제시되었다. UHF 레이더의 $C_n^2$ 연직 분포에서 첨두는 대류 경계층의 정상부뿐만 아니라 잔류층의 정상부나 구름층에서도 발생하였다. 약한 태양 복사로 연직 혼합이 뚜렷하지 않은 경우에 대류 경계층 고도에 상응하는 $C_n^2$ 첨두는 레윈존데(rawinsonde) 관측 자료로부터 추정된 대류 경계층 고도보다 약간 낮았다. 반면에, 강한 태양 복사에 의해 연직 혼합이 강하고 유입대에서 ${\theta}_v$와 q의 연직 기울기가 매우 클 경우에 대류 경계층 고도에 상응하는 $C_n^2$ 첨두는 레윈존데 관측 자료로부터 추정된 대류 경계층 고도와 잘 일치하였다. $C_n^2$ 첨두의 고도를 대류 경계층 고도로 결정하는 최대 후방 산란 강도 방법(maximurn backscatter intensity method)은 $C_n^2$ 연직 분포에서 하나의 첨두가 있을 경우에는 오류 없이 대류 경계층 고도를 추정하였지만 대류 경계층 고도 위에 잔류층이나 구름층이 있을 경우에는 대류 경계층 고도를 잘못 추정하였다. 본 연구에서 새로이 제시된 방법은 UHF 레이더의 $C_n^2$와 ${\sigma}_w$ 자료를 이용하여 대류 경계층 고도로부터 오는 $C_n^2$ 첨두를 잔류층이나 구름층으로부터 오는 $C_n^2$ 첨두로부터 구별하여 오류 없이 대류 경계층 고도를 추정하였다. 또한 이 방법은 대류 경계층 고도의 일반화 추정에 적용되었으며, 후방 산란 강도의 연직 분포에서 두개의 첨두가 존해할 경우에도 더욱 신뢰성 있고 안정되게 대류 경계층 고도를 실시간으로 추정하였다.

• Molecules and Cells
• /
• 제41권4호
• /
• pp.320-330
• /
• 2018

${\delta}$-Catenin, a member of the p120-catenin subfamily of armadillo proteins, reportedly increases during the late stage of prostate cancer. Our previous study demonstrates that ${\delta}$-catenin increases the stability of EGFR in prostate cancer cell lines. However, the molecular mechanism behind ${\delta}$-catenin-mediated enhanced stability of EGFR was not explored. In this study, we hypothesized that ${\delta}$-catenin enhances the protein stability of EGFR by inhibiting its lysosomal degradation that is mediated by c-casitas b-lineage lymphoma (c-Cbl), a RING domain E3 ligase. c-Cbl monoubiquitinates EGFR and thus facilitates its internalization, followed by lysosomal degradation. We observed that ${\delta}$-catenin plays a key role in EGFR stability and downstream signaling. ${\delta}$-Catenin competes with c-Cbl for EGFR binding, which results in a reduction of binding between c-Cbl and EGFR and thus decreases the ubiquitination of EGFR. This in turn increases the expression of membrane bound EGFR and enhances EGFR/Erk1/2 signaling. Our findings add a new perspective on the role of ${\delta}$-catenin in enhancing EGFR/Erk1/2 signaling-mediated prostate cancer.

• Journal of Computing Science and Engineering
• /
• 제4권4호
• /
• pp.313-349
• /
• 2010

In this paper, we study the data interoperability problem of web services in terms of XML schema compatibility. When Web Service A sends XML messages to Web Service B, A is interoperable with B if B can accept all messages from A. That is, the XML schema R for B to receive XML instances must be compatible with the XML schema S for A to send XML instances, Le., A is a subschema of B. We propose a formal model called Schema Automaton (SA) to model W3C XML Schema (XSD) and develop several algorithms to perform different XML schema computations. The computations include schema minimization, schema equivalence testing, subschema testing, and subschema extraction. We have conducted experiments on an e-commerce standard XSD called xCBL to demonstrate the practicality of our algorithms. One experiment has refuted the claim that the xCBL 3.5 XSD is backward compatible with the xCBL 3.0 XSD. Another experiment has shown that the xCBL XSDs can be effectively trimmed into small subschemas for specific applications, which has significantly reduced the schema processing time.

• Genomics & Informatics
• /
• 제7권2호
• /
• pp.53-56
• /
• 2009

Recent evidence has strongly suggested that the CAP/TC10 pathway is involved in the trafficking, docking, and fusion of vesicles containing the insulin-responsive glucose transporter Glut4 to the plasma membrane. However, little is known about how the genes employed in the CAP/TC10 pathway are associated with the development of type 2 diabetes mellitus. In this study, we sequenced 4 genes of the CAP/TC10 pathway [SORBS1, CBL, CRK, and RHOQ] in 24 individuals to identify genetic variations in these loci. A total of 48 sequence variants were identified, including 23 novel variations. To investigate the possible association with type 2 diabetes mellitus, 3 single nucleotide polymorphisms from SORBS1, 3 from CBL, and 4 from RHOQ were genotyped in 1122 Korean type 2 diabetic patients and 1138 nondiabetic controls. Using logistic regression analysis, 1 significant association between SNP rs1376405 in RHOQ and type 2 diabetes mellitus [OR = 8.714 (C.I. 1.714-44.29), p = 0.009] was found in the recessive model. Our data demonstrate a positive association of the RHOQ gene in the CAP/TC10 pathway with T2DM in the Korean population.

• Asian Pacific Journal of Cancer Prevention
• /
• 제14권7호
• /
• pp.4279-4282
• /
• 2013

Background: The activation and inactivation of receptor tyrosine kinases are tightly regulated to ensure faithful replication of cells. After having transduced extracellular growth activating signals, activated EGFR is subjected to downregulation either by clathrin mediated endocytosis or c-Cbl mediated proteasome degradation depending on the ligand concentration. c-Cbl is an ubiquitin ligase which requires a phosphorylated tyrosine residue at position 1045 in the cytoplasmic domain of EGFR to interact and add ubiquitin molecules. While activating mutations in exons 19 and 21 have been associated with the development of several cancers, the status of mutations at tyrosine 1045 coding exon 27 of EGFR remain to be investigated. Consistently, defective phosphorylation at 1045 has been associated with sustained phosphorylation of EGFR in non-small lung carcinomas. Hence in the present study we investigated the genetic status of the tyrosine 1045 coding site within exon 27 of EGFR gene to explore for possible occurrence of mutations in this region, especially since no studies have addressed this issue so far. Materials and Methods: Tumor chromosomal DNA isolated from thirty five surgically excised oral squamous cell carcinoma tissues was subjected to PCR amplification with intronic primers flanking the tyrosine 1045 coding exon 27 of EGFR gene. The PCR amplicons were subsequently subjected to direct sequencing to elucidate the mutation status. Results: Sequence analysis identified no mutations in the tyrosine 1045 codon of EGFR in any of the thirty five samples that were analyzed. Conclusions: The lack of identification of mutation in the tyrosine 1045 codon of EGFR suggests that mutations in this region may be relatively rare in oral squamous cell carcinomas. To the best of our knowledge, this study is the first to have explored the genetic status of exon 27 of EGFR in oral squamous cell carcinoma tissue samples.

• Current Applied Physics
• /
• 제18권12호
• /
• pp.1592-1599
• /
• 2018

The present study deals with the effect of dual cathode buffer layer (CBL) on the performance of bilayer of 4,4'-cyclohexylidenebis[N,N-bis(4-methylphenyl)benzenamine] (TAPC) and fullerene (C70)-based organic solar cell (OSC) with low donor concentration. OSC devices with CBLs have been fabricated using thermal vapor deposition technique. We report the use of lithium fluoride (LiF) and molybdenum trioxide ($MoO_3$) as CBLs. The insertion of LiF between C70 and aluminium (Al) electrode enhances the power conversion efficiency (PCE) of device from 1.89% to 2.47% but quenching of photogenerated excitons is observed at interface of C70 and LiF layers. Incorporation of $MoO_3$ between LiF and Al electrode further enhances PCE of device to 3.51%. This has also improved the material quality and device properties, by preventing the formation of gap states and diminishing exciton quenching.