• BMB Reports
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• v.34 no.1
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• pp.33-38
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• 2001

The human PTK6 (also known as Brk) polypeptide, which is deduced from its full-length cDNA, represents a non-receptor protein tyrosine kinase (PTK). It contains SH3, SH2, and tyrosine kinase catalytic domains that are closely related to Src family members. We generated an antihuman PTK6 antibody by immunizing rabbits with a PTK6-specific oligopeptide conjugated to BSA, which corresponds to 11 amino acid residues near the C-terminus. An immunoblot analysis with the antibody detected an expected 52-kDa band in various mammalian transformed cell lines. Immunoprecipitation and immunoblot analyses demonstrated that PTK6 is phosphorylated on the tyrosine residues) and interacts with approximately a 23-kDa tyrosine-phosphorylated polypeptide (most likely a substrate of PTK6) in breast carcinoma T-47D cells. An immunofluorescence analysis demonstrated that PTK6 is localized throughout the cytoplasm of T-47D cells. These results support a possible role for PTK6 in the intracellular signal transduction through tyrosine phosphorylation.

• Bulletin of the Korean Chemical Society
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• v.30 no.5
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• pp.1043-1046
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• 2009

Human protein tyrosine kinase-6 (PTK6) is a member of the non-receptor protein tyrosine kinase family and it is found in two-thirds of all breast tumors. Very recently, we proposed that the SH3 domain of PTK6 interacts with the linker region (Linker) between the SH2 and kinase domains, proving that the interaction between SH3 domain and Linker plays an important role in auto-inhibition mechanism. Residues from 1 to 191 corresponding region of SH3-SH2-Linker (SH32L) of PTK6 was cloned into the pET32a expression vector with Tobbaco etch virus (TEV) protease enzyme site by sequence homology and 3D structural model. The purified PTK6-SH32L was determined as a monomer conformation in solution. The amide proton resonances in the $^{15}N-^{1}H$ 2D-HSQC spectrum suggest that PTK6-SH32L possesses disordered structural region of the flexible/unstructured linker region. In addition, the backbone amide proton chemical shifts of the SH3 domain in the PTK6-SH32L differ from that of the independent domain, indicating that intra-molecular interaction between SH3 and Linker in the PTK6-SH32L is present.

• Journal of Life Science
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• v.17 no.2 s.82
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• pp.179-184
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• 2007

PTK6, an intracellular protein tyrosine kinase, is significantly overexpressed in a majority of breast cancers and has a role in promoting the proliferation of the cancer cells, but not of normal cells. Here, we report high-level production of the catalytic unit of PTK6 fused with Drosophila peptidoglycan recognition protein (PGRT)-LB, in the baculovirus system. We first found that the PGRP-LB was potentially useful as a fusion partner to increase the yield of heterologous protein in the baculovirus system. The purified recombinant protein exhibited a 1.5-fold activity with much higher yield than the bacterially-expressed protein. The protein expressed in the baculovirus system will be useful for the crystallization to determine its crystal structure helping understand the molecular mechanism of PTK6 and design its inhibitors.

• BMB Reports
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• v.35 no.3
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• pp.343-347
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• 2002

The human protein tyrosine kinase-6 (PTK6) polypeptide that is deduced from the cDNA sequence contains a Src homology (SH) 3 domain, SH2 domain, and catalytic domain of tyrosine kinase. We initiated biochemical and NMR characterization of PTK6 SH3 domain in order to correlate the structural role of the PTK6 using circular dichroism and heteronuclear NMR techniques. The circular dichroism data suggested that the secondary structural elements of the SH3 domain are mainly composed of $\beta$-sheet conformations. It is most stable when the pH is neutral based on the pH titration data. In addition, a number of cross peaks at the low-field area of the proton chemical shift of the NMR spectra indicated that the PTK6 SH3 domain retains a unique and folded conformation at the neutral pH condition. For other pH conditions, the SH3 domain became unstable and aggregated during NMR measurements, indicating that the structural stability is very sensitive to pH environments. Both the NMR and circular dichroism data indicate that the PTK6 SH3 domain experiences a conformational instability, even in an aqueous solution.

• Journal of Korean Neurosurgical Society
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• v.65 no.1
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• pp.64-73
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• 2022

Objective : To evaluate the surgical outcomes of partial pedicle subtraction osteotomy (PPSO) in patients with thoracolumbar fractures and compare the outcomes of PPSO for burst fractures with those for posttraumatic kyphosis (PTK). Methods : From June 2013 to May 2019, 20 consecutive adult patients underwent PPSO for thoracolumbar fractures at the levels of T10 to L2. Of these patients, 10 underwent surgery for acute fractures (burst fractures), and 10 for sequelae of thoracolumbar fractures (PTK). Outcomes of PPSO were evaluated and compared between the groups. Results : Twenty patients (each 10 patients of burst fractures and PTK) with a mean age of 64.7±11.1 years were included. The mean follow-up period was 21.8±11.0 months. The mean correction of the thoracolumbar angle was -34.9°±18.1° (from 37.8°±20.5°preoperatively to 2.8°±15.2° postoperatively). The mean angular correction at the PPSO site was -38.4°±13.6° (from 35.5°±13.6° preoperatively to -2.9°±14.1° postoperatively). The mean preoperative sagittal vertical axis was 93.5±6.7 cm, which was improved to 37.6±35.0 cm postoperatively. The mean preoperative kyphotic angle at the PPSO site was significant greater in patients with PTK (44.8°±7.2°) than in patients with burst fractures (26.2°±12.2°, p=0.00). However, the mean postoperative PPSO angle did not differ between the two groups (-5.9°±15.7° in patients with burst fractures and 0.2°±12.4° in those with PTK, p=0.28). The mean angular correction at the PPSO site was significantly greater in patients with PTK (-44.6°±10.7°) than in those with burst fractures (-32.1°±13.7°, p=0.04). The mean operation time was 188.1±37.6 minutes, and the mean amount of surgical bleeding was 1030.0±533.2 mL. There were seven cases of perioperative complications occurred in five patients (25%), including one case (5%) of neurological deficit. The operation time, surgical bleeding, and complication rates did not differ between groups. Conclusion : In cases of burst fracture, PPSO provided enough spinal cord decompression without corpectomy and produced sagittal correction superior to that achieved with corpectomy. In case of PTK, PPSO achieved satisfactory curve correction comparable to that achieved with conventional PSO, with less surgical time, less blood loss, and lower complication rates. PPSO could be a viable surgical option for both burst fractures and PTK.

• Journal of Korea Multimedia Society
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• v.12 no.9
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• pp.1323-1332
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• 2009

In this paper, we analyze security weakness of 4-Way Handshake in IEEE 802.11i and propose fast and secure 2-Way Handshake mechanism. Compute PTK(Pairwise Transient Key) using sequence number instead of random numbers in order to protect Replay attack and DoS attack. Also, proposed 2-Way Handshake mechanism can mutual authenticate between mobile station and access point and derive PTK using modified Re-association Request and Re-association Response frames. And, compare with others which are fast and secure Handoff mechanisms.

• Journal of Digital Convergence
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• v.10 no.11
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• pp.565-577
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• 2012

Various factors affecting teachers' self-confidence exist in math class using technology such as graphic calculators. For example, internal factors such as teachers' attitude and external factors such as school administrators or colleague's support can be considered. Pedagogical Technology Knowledge(PTK) is the very important factor which determines teacher's self-confidence in educational technology, and the development of PTK is composed of teacher's perception on the technology and its application and instrumentation. This study investigated 19 pre-service and current middle and high school teachers in the respect of their change of self-confidence, attitude, expertise on pedagogical technology, and quality of math class. These are anlayzed with the concept of instrumentation and instrumentalization through various experiences like graphic calculator, GPS and AutoGraph. The result indicated that constraints or obstacles did not affect much if teachers' attitude and self-confidence were strong. Particularly teachers' firm will to learn about technology and their confidence on its value are the critical factors in using technology for mathematics class.

• Radiation Oncology Journal
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• v.18 no.1
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• pp.51-58
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• 2000

Purpose :The effect of PTK inhibitors (herbimycin A and genistein) on the induction of radiation-induced apoptosis in Ph-positive KS62 leukemia cell line was investigated. Materials and Methods :K562 cells in exponential growth phase were irradiated with a linear accelerator at room temperature. For 6 MV X-ray irradiation and drug treatment, cultures were initiated at 2×106 cells/mL. The cells were irradiated with 10 Gy. Stock solutions of herbimycin A and genistein were prepared in dimethyl sulphoxide (DMSO). After incubation at 37$^{\circ}C$ for 0$\~$48 h, the extent of apoptosis was determined using agarose gel electrophoresis and TUNEL assay. The progression of cells through the cell cycle after irradiation and drug treatment was also determined with flow cytometry. Western blot analysis was used to monitor bel-2, bel-X$_{L}$ and bax protein levels. Results :Treatment with 10 Gy X-irradiation did not result in the induction of apoptosis. The HMA alone (500 nM) also failed to induce apoptosis. By contrast, incubation of K562 cells with HMA after irradiation resulted in a substantial induction of nuclear condensation and fragmentation by agarose gel electro-phoresis and TUNEL assay. Genistein failed to enhance the ability of X-irradiation to induce DNA fragmentation. Enhancement of apoptosis by HMA was not attributable to downregulation of the bel-2 or bel-X$_{L}$ anti-apoptotic proteins. When the cells were irradiated and maintained with HMA, the percentage of cells in G2/M phase decreased to 30$\~$40$\%$ at 48 h. On the other hand, cells exposed to 10 Gy X-irradiation alone or maintained with genistein did not show marked cell cycle redistribution. Conclusion : We have shown that nanomolar concentrations of the PTK inhibitor HMA synergize with X-irradiation in inducing the apoptosis in Ph (+) K562 leukemia cell line. While, genistein, a PTK inhibitor which is not selective for p210$^{bcr/abl}$ failed to enhance the radiation induced apoptosis in KS62 cells. It is unlikely that the ability of HMA to enhance apoptosis in K562 cells is attributable to bel-2 family. It is plausible that the relationship between cell cycle delays and cell death is essential for drug development based on molecular targeting designed to modify radiation-induced apoptosis.

• Journal of Microbiology and Biotechnology
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• v.15 no.4
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• pp.756-766
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• 2005

The signaling mechanism underlying aburatubolactam C-induced FasL upregulation was investigated in human Jurkat T cells. After treatment with aburatubolactam C, the src-family PTKs $p56^{lck}\;and\;p59^{fyn}$, and MAP kinases ERK2 and JNK1, were activated prior to FasL upregulation; Both $p56^{lck}\;and\;p59^{fyn}$ were directly activated 2.4- and 2.2-fold, respectively, in vitro by aburatubolactam C. The aburatubolactam C-induced cellular changes, including the activation of ERK2 and INK1, and FasL upregulation, were completely prevented by the PTK inhibitor genistein. The activation of protein kinase C (PKC$\delta,\;\epsilon\;and\;\mu$ was also induced following aburatubolactam C treatment. Although the activation of $p56^{lck}$ and tyrosine phosphorylation of the cellular proteins were not blocked by the PKC inhibitor GFl09203X, the activation of ERK2 was completely abrogated, along with a detectably enhanced JNK1 activation; FasL upregulation, and apoptosis. However, the FasL upregulation and apoptosis were significantly inhibited by the PKC activator PMA, with a remarkable increase in the ERK2 activation. The cytotoxic effect of aburatubolactam C was reduced in the presence of the anti-Fas neutralizing antibody ZB-4. Although ectopic expression of Bcl-2 failed to completely block the cytotoxicity of aburatubolactam C, it was clearly suppressed. The c-Fos mRNA expression was upregulated in a biphasic manner, where the second phasic expression overlapped with the FasL upregulation. Accordingly, these results demonstrate that aburatubolactam C-induced apoptosis is exerted, at least in part, by FasL upregulation dictated by activation of the PTK ($p56^{lck}\;and\;p59^{fyn}$) /JNKI pathway, which is negatively affected by the concurrent activation of the PKC/ERK2 pathway proximal to PTK activation.

• Physical Therapy Korea
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• v.31 no.1
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• pp.89-89
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• 2024