• Title, Summary, Keyword: EGF receptor

Search Result 91, Processing Time 0.04 seconds

Dependence of High Affinity Binding of Epidermal Growth Factor on Receptor Cytoplasmic Domain (Receptor Cytoplasmic 영역에 의존하는 EGF의 고친화성 결합)

  • 강용호
    • KSBB Journal
    • /
    • v.7 no.3
    • /
    • pp.201-208
    • /
    • 1992
  • Cell surface binding of epidermal growth factor(EGF) to EGF receptors was studied for a series of site-directed receptor mutants transfected into B82 mouse fibroblasts. Scatchard plots for truncation mutant receptors significantly lost nonlinearity for truncations below residue 1022. Transient plots of dissociation kinetics exhibited biphasic behavior for all receptor types, but the fraction of receptor in slow-dissociating form was reduced by an order of magnitude for the truncation mutants below residue 1022. Comparison of dissociation kinetics between control cells and cells treated with Triton X-100 revealed no significant variation for the slow-dissociating receptor form, but a noticeable variation was observed for the fast-dissociating receptor form when EGF receptors were truncated below residue 991. These results suggest that high affinity of EGF binding at cell surface depend on the EGF receptor cytoplasmic region.

  • PDF

Epidermal Growth Factor Receptors Increase in Rabbit Embryonal Implantation (배아착상에 대한 Epidermal Growth Factor 수용체의 동태)

  • Lee, Yu-Il
    • Clinical and Experimental Reproductive Medicine
    • /
    • v.18 no.2
    • /
    • pp.181-187
    • /
    • 1991
  • Epidermal growth facter(EGF)는 내열성이 강하고 분자량이 6045 dalton인 단쇄상의 polypeptide로써, Cohen에 의해 생쥐의 악하선에서 처음 발견된 이래, 여러학자들에 의해 많은 연구가 되어왔다. 인체의 EGF는 urogastrone이라고도 불리우며, 인체의 소변에서 처음 검출되었고 분자구조 및 생리작용이 생쥐의 EGF와 매우 유사한 것으로 판명되었다. EGF의 자세한 작용기전은 확실히 규명되어있지는 않지만 세포의 증식과 분화를 촉진시키며 위산의 분비를 억제시킨다고 알려져 있다. 또한 EGF receptor는 분자량이 170,000${\sim}$180,000dalton인 세포표면의 polypeptide로써 인체, 쥐, 닭, 소 등의 세포막조직에 특이하게 결합되어 있다. 최근 수년동안 몇몇 학자들에 의해 EGF가 배아와 태아 및 태반의 성장을 촉진시키고 chorionic gonadotrophin과 placental lactogen의 분비를 증진하는데 기여할 것이라고 가정되어 왔다. 그러나 아직까지 배아착상에 대한 EGF의 작용여부에 관해서는 발표된 문헌이 없어 저자는 radioreceptor assay를 이용하여 EGF receptor binding과 토끼의 배아착상과의 관계를 규명하고자 임신경과에 따른 착상부위와 비착상부위의 자궁 및 태아측 태반과 모체측 태반을 분리취득하고 receptor binding assay를 시행하여 다음과 같은 결론을 얻었다. 1. 전임신군과 비임신군의 자궁조직의 membrane fraction으로부터 specific한 EGF receptor binding이 관찰되었다. 2. 착상전 임신 3일에 자궁조직의 EGF receptor수는 4.72 +0.16($10\;mol/{\mu}g$)로 비임신시보다 의의있게 증가되어 있었고(p<0.01), 착상시기인 임신 7일에는 착상된 부위에서 20.33+6.58로 훨씬 더 높은 측정치를 나타내었다(p<0.05). 3. 착상이후 가장 먼저 취득된 임신 14일의 태아측 태반은 모체측 태반의 1.39+0.49에 비해 훨씬 높은 11.94+1.97의 EGF receptor 측정치를 보였다 (p<0.01). 4. 이상의 소견들로 보아 EGF가 토끼의 배아착상에 밀접한 관련이 있을 것으로 추측되며, 이러한 착상전후의 EGF의 작용은 태아측으로부터 일 것으로 예상된다.

  • PDF

Requirement of EGF Receptor Kinase for Signaling by Calcium-Induced ERK Activation and Neurite Outgrowth in PC12 Cells

  • Park, Jung-Gyu;Jo, Young-Ah;Kim, Yun-Taik;Yoo, Young-Sook
    • BMB Reports
    • /
    • v.31 no.5
    • /
    • pp.468-474
    • /
    • 1998
  • Membrane depolarization in PC12 cells induces calcium influx via an L-type voltage-sensitive calcium channel (L-VSCC) and increases intracellular free calcium, which leads to tyrosine phosphorylation of epidermal growth factor (EGF) receptor and the associated adaptor protein, She. This activated EGF receptor complex then can activate mitogen-activated protein (MAP) kinase, as in nerve growth factor (NGF) receptor activation. In the present study, we investigated the role of EGF receptor in the signaling pathway initiated by membrane depolarization of PC12 cells. Prolonged membrane depolarization induced phosphorylation of extracellular signal-regulated kinase (ERK) within 1 min in undifferentiated PC12 cells. Pretreatment of PC12 cells with the calcium chelator EGTA abolished depolarization-stimulated ERK phosphorylation, but NGF-induced phosphorylation of ERK was not affected. The chronic treatment of phorbol ester, which down-regulated the activity of protein kinase C (PKC), did not affect the phosphorylation of ERK upon depolarization. In the presence of an inhibitor of EGF receptor, neither depolarization nor calcium ionophore increased the level of ERK phosphorylation. These data imply that the EGF receptor is functionally necessary to activate ERK and neurite outgrowth in response to the prolonged depolarization in PC12 cells, and also that PKC is apparently not involved in this signaling pathway.

  • PDF

Antitumor activities of hypericin as a protein tyrosine kinase blocker

  • Kil, Kwang-Sup;Yum, Young-Na;Seo, Seung-Hoon;Lee, Kyung-Tae
    • Archives of Pharmacal Research
    • /
    • v.19 no.6
    • /
    • pp.490-496
    • /
    • 1996
  • Naphtodianthrone hypericin produced a potent antitumor activity in vitro against several tumor cells. However, it did not show any cytotoxicity on normal cells such as Macaccus rheus monkey kidney cells (MA-104) and primary cultured rat hepatocytes up to $500{\mu}M$ concentration. Hypericin added to A431 human epidermoid carcinoma cell membrane inhibited the autophosphorylation of the epidermal growth factor (EGF) receptor and the tyrosine phosphorylation of RR-SRC peptide catalyzed by an EGF-receptor. Similarly, treatment of the A431 cells with hypericin inhibited the tyrosine phosphorylation of EGF-dependent endogenous EGF-receptor by western blotting analysis. Hypericin also inhibited the T cell PTK, $P56^{lck}$, in a dose-dependent fashion with an $IC_{50}=5{\mu}M$. The tyrosine phosphorylation, on RR-SRC peptide and EGF-induced receptor autophosphorylation, either in vitro or in intact cells was inhibited by hypericin at the same concentration as that in A431 cell proliferation. These data suggest that hypericin directly inhibits EGF-receptor and $P56^{lck}$ PTK activity in vitro and can mediate such action in vivo.

  • PDF

Direct tyrosine phosphorylation of Akt/PKB by epidermal growth factor receptor (EGF 수용체에 의한 Akt/PKB의 tyrosine 인산화에 대한 연구)

  • Bae, Sun-Sik;Choi, Jang-Hyun;Yun, Sung-Ji;Kim, Eun-Kyung;Oh, Yong-Suk;Kim, Chi-Dae;Suh, Pann-Ghill
    • Journal of Life Science
    • /
    • v.17 no.2
    • /
    • pp.185-191
    • /
    • 2007
  • Akt/PKB plays pivotal roles in many physiological responses such as proliferation, differentiation, apoptosis, and angiogenesis. Here we show that tyrosine phosphorylation of Akt/PKB is essential for the subsequent phosphorylation at $Thr^{\308}$. Tyrosine phosphorylation of Akt/PKB was induced by stimulation of COS-7 cells with epidermal growth factor receptor (EGF) and its phosphorylation was significantly enhanced by constitutive targeting of Akt/PKB to the plasma membrane by myristoylation. Interestingly, incubation of affinity purified Myc-tagged Akt/PKB with purified EGF receptor resulted in tyrosine phosphorylation as well as $Ser^{\473}$ phosphorylation of Akt/PKB. In addition, tyrosine-phosphorylated Akt/PKB could directly associate with activated EGF receptor in vitro. Finally, alanine mutation at putative tyrosine phosphorylation site $(Tyr^{\326})$ abolished EGF induced $Thr^{\308}$ phosphorylation of wild type as well as constitutively active form of Akt/PKB. Given these results we suggest here that direct tyrosine phosphorylation of Akt/PKB by EGF receptor could be another mechanism of EGF-induced control of many physiological responses.

Chemical Synthesis and Determination of Biological Activity of the Epidermal Growth Factor-Like Domain of Mouse Betacellulin

  • Shin, Song-Yub;Kang, Shin-Won;Ha, Jong-Myung
    • BMB Reports
    • /
    • v.28 no.2
    • /
    • pp.87-93
    • /
    • 1995
  • To investigate the biological functions of the EGF-like domain of mouse betacellulin (BTC), mouse BTC(33-80), a 48-residue peptide corresponding to the EGF-like domain, was synthesized by stepwise solidphase methods using a 9-fluorenylmethoxycarbonyl (Fmoc) strategy. The homogeneity of synthetic mouse BTC(33-80) was confirmed by analytical reversed phase (RP)-HPLC, amimo acid analysis, and fast atom bombardment mass spectrometer (FAB-MS). Three disulfide bond pairings of synthetic mouse BTC(33-80) were established by amino acid analysis of cysteine-containing fragments derived from thermolytic digestion. These were consistent with the pairings of EGF and transforming growth factor ($TGF-{\alpha}$). The EGF-Iike domain of mouse BTC showed equipotent activity in both EGF-receptor binding on A-431 epidermoid carcinoma cells, and mitogenesis on NIH-3T3 fibroblast cells, as compared with authentic h-EGF. Results suggest that the EGF-Iike domain of BTC plays a significant role in mitogenic activity with an EGF-receptor mediated system.

  • PDF

Expression of Epidermal Growth Factor-Receptor (EGF-R) on the Inner Cell Mass (ICM) of Bovine IVM/IVF/IVC Blastocyst (체외생산된 소 배반포기배 ICM세포에서의 EGF-R 발현)

  • ;N.L. First
    • Korean Journal of Animal Reproduction
    • /
    • v.21 no.1
    • /
    • pp.39-46
    • /
    • 1997
  • 본 연구는 체외생산된 소 배반포기배의 inner cell mass (ICM) 세포에서 epidermal growth factor-receptor (EGF-R)의 발현 유무를 immunosurgery와 indirect immunofluorescence (간접 면역 형광방법)을 이용하여 조사하고자 실시하였다. 본 실험에 사용된 ICM 세포는 체외수정 후 7∼8일째에 회수된 소 배반포기배로부터 immunosurgery 방법을 실시하여 얻어졌으며, 회수된 ICM세포는 live/dead 염색방법을 통한 생사 유무와 EGF-R 발현 유무 조사에 공시되었다. 특히, 배반포기배에 대한 immunosurgery를 위해 trophectoderm 세포에 대한 rabbit anti-bovine trophectoderm cell antibody (RABTE)를 제조하여 사용하였다. 결과를 요약하면 다음과 같다. ICM세포의 회수율은 RABTE와 guinea pig serum (complement)에 각각 15∼30분과 15∼60분동안 처리했을 경우 16.7∼74.2%였으며, 또한 처리시간이 각각 30분과 30분일 때 가장 높은 회수율(74.2%)을 얻었다. Immunosurgery 후 얻어진 ICM세포의 생존 유무를 조사하기 위해 live/dead 염색 방법을 이용하였던바, ICM세포의 생존율은 complement가 60분 처리된 군(69.3%)을 제외한 모든 처리군에서 84.0∼91.6%의 높은 생존율을 나타냈다. 또한, 회수된 ICM세포에 대한 EGF-R의 존재를 확인하였다. 따라서, ICM세포에서의 EGF-R의 발현은 인위적으로 첨가된 EGF의 이용 가능성을 높임으로서 체외에서의 착상전 배 발달을 증진시킬 수 있을 것으로 사료된다.

  • PDF

Translocation of Annexin I to the Nucleus by Epidermal Growth Factor in A549 Cells

  • Rhee, Hae-Jin;Kim, Seung-Wook;Soo-Ok, Lee;Park, Young-Min;Na, Doe-Sun
    • BMB Reports
    • /
    • v.32 no.1
    • /
    • pp.28-32
    • /
    • 1999
  • Annexin I (also called lipocortin 1), a 37-kDa member of the annexin family of proteins, has been implicated in the mitogenic signal transduction by epidermal growth factor (EGF). Annexin I is phosphorylated by the EGF signal, however, the role of annexin I in the EGF signal transduction is still unknown. To transduce extracellular signals into the intracellular targets, selective translocation of the signaling molecules to their targets would be necessary. In this study, we examined the subcellular locations of annexin I during EGF signal transduction. Treatment of A549 cells with EGF resulted in the translocation of cytoplasmic annexin I to the nucleus and perinuclear region as determined by Western blot and immunofluorescent staining. The nuclear translocation of annexin I was inhibited by tyrphostin AG 1478 and genistein, the inhibitors of EGF receptor kinase and downstream tyrosine kineses, respectively. Pretreatment of cells with cyclohexamide did not inhibit the nuclear translocation. The results suggest that nuclear translocation of annexin I is controlled by a series of kinase dependent events in the EGF receptor signaling pathway and may be important in tranducing the signals by EGF.

  • PDF

The Effect of EGF, T3 and HB-EGF on Human Periodontal Fibroblasts (EGF, T3, HB-EGF 가 치주인대섬유모세포에 미치는 영향)

  • Hong, Eun-Kyoung;Cha, Jeong-Heon;Kim, Yun-Tae;Choi, Byung-Jai;Kim, Seong-Oh
    • THE JOURNAL OF THE KOREAN ACADEMY OF PEDTATRIC DENTISTRY
    • /
    • v.34 no.3
    • /
    • pp.438-446
    • /
    • 2007
  • Viable cells of periodontal ligament would be an important factor for the successful replantation of an avulsed tooth. Therefore, it is critical to choose the storage medium for the preservation of traumatically avulsed teeth. Growth factors and hormones could be considered for the therapeutic application of the maintenance of viable periodontal ligament fibroblasts (PDLFs). Epidermal growth factor (EGF) has been suggested as an important player for the regeneration and wound healing process on other tissues. Therefore, EGF was evaluated for the therapeutic application on avulsed teeth. In addition, the synergic effect of EGF with tri-iodothyronine (T3) and heparin-binding epidermal growth factor-like growth factor (HB-EGF). The cell proliferation of PDLFs was determined by MTT assay and increased dose-dependently up to 10 ng/ml in the presence of EGF. Maximum cellular growth was shown at the concentration of 10 ng/ml EGF. Also, EGF promoted the wound healing of PDLFs examined by in vitro wound healing assay. Combined effects of EGF with T3 or HB-EGF on the proliferation of PDLFs were also studied. Interestingly, EGF showed the synergic effect on the proliferation of PDLFs with T3 and HB-EGF. To find out the mechanism of the synergic effect of EGF and T3, the effect of T3 on the expression of endogenous EGF receptor was determined by RT-PCR. The result was that T3 enhanced the expression of EGF receptor in PDLFs. It suggested that EGF might be a good choice for a therapeutic application, which can be used as combination with T3 and HB-EGF.

  • PDF

Signal Transduction of MUC5AC Expression in Airway Mucus Hypersecretory Disease (기도의 점액 과분비 질환에서 MUC5AC의 발현의 신호 전달 경로에 관한 연구)

  • Shim, Jae Jeong
    • Tuberculosis and Respiratory Diseases
    • /
    • v.55 no.1
    • /
    • pp.21-30
    • /
    • 2003
  • Background : Mucin synthesis in airways has been reported to be regulated by the epidermal growth factor receptor (EGFR) system. Epidermal growth factor receptor transactivation was identified as a critical element in G-protein-coupled receptors (GPCRs)-induced mitogenic signaling. EGF receptor transactivation by G-protein-coupled receptors requires metalloproteinase cleavage of proHB-EGF. This study was hypothesized that lipopolysaccharide (LPS)-induced mucin production associates with epidermal growth factor receptor transactivation, and MUC5AC production associates with epidermal growth factor receptor transactivation by G-protein-coupled receptors that regulates by metalloproteinase. Method : MUC5AC mucin production was examined in NCI-H292 cells and MUC5AC protein synthesis was assessed using ELISA. For the evaluation of mechanism of LPS-induced MUC5AC production, $TNF{\alpha}$ was measured using ELISA with or without pretreatment of heterotrimeric G-protein inhibitor, mastoparan. MUC5AC protein was measure with pretreatment of polyclonal $TNF{\alpha}$ antibody or mastoparan on LPS-induced MUC5AC production. For the evaluation of relation of G-protein and MUC5AC production, G-protein stimulant, mastopara-7, or matrix metalloproteinase, ADAM10, was added to NCI-H292 cells. MUC5AC protein was measure with pretreatment of polyclonal EGF antibody on mastoparan-7-induced MUC5AC production. Results : LPS alone did not increase significantly MUC5AC production. LPS with $TNF{\alpha}$ induced dose-dependently MUC5AC production in NCI-H292 cells. LPS increased dose-dependently $TNF{\alpha}$ secretion, which was inhibited by mastoparan. LPS with $TNF{\alpha}$-induced MUC5AC production was inhibited by neutralizing polyclonal $TNF{\alpha}$ antibody, mastoparan or AG 1472. Mastoparan-7 or ADAM10 increased dose-dependently MUC5AC production, which was inhibited by polyclonal neutralizing EGF antibody. Conclusion : In LPS-induced MUC5AC synthesis, LPS causes $TNF{\alpha}$ secretion, which induces EGFR expression. EGFR tyrosine kinase phosphorylation result in MUC5AC production. EGF-R transactivation by G-protein-coupled receptors requires matrix metalloproteinase cleavage of proHB-EGF.