1998 Fiscal Year Final Research Report Summary
Study of the activity of proHB-EGF complex.
| Project/Area Number |
09680706
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (C)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
Cell biology
|
|---|
| Research Institution | Institute of Life Science, Kurume University |
|---|
Principal Investigator |
IWAMOTO Ryo Institute of Life Science, Kurume University Assistant Professor, 分子生命科学研究所, 助手 (10213323)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
UMATA Toshiyuki Institute of Life Science, Kurume University Assistant Professor, 分子生命科学研究所, 助手 (30213482)
|
|---|
| Project Period (FY) |
1997 – 1998
|
| Keywords | HB-EGF / EGFreceptor / juxtacrine / cell-to-cell signalling / ectodomain shedding / protein kinase C / MDC9 / ADAM family |
|---|
| Research Abstract |
We have studied the membrane-anchored form of heparin-binding EGF-like growth factor (proHB-EGF) and its physiological function. Recently we demonstrated that proHB-EGF and CD9 form a complex with integrin alpha3betal at cell-cell contact sites of Vero cells. To study the function of proHB-EGF complex, in this project, we studied 1) the biological activity of proHB-EGF, 2) the mechanism of the ectodomain shedding of proHB-EGF, and 3) identification and characterization of a novel component of proHB-EGF complex.
1)Analysis of the biological activity of proHB-EGF We studied the biological activity of proHB-EGF by using a model in which proHJB-EGF-expressing effector cells were co-cultured with EGFR-expressing target cells. From this experimental system, we found that proHB-EGF induces growth inhibition and subsequent apoptosis of the EGER-expressing target cells. Moreover, we found that the inhibitory signal induced by proHB-EGF is mediated via EGFR and that the cytoplasmic domain of EGFR
… More
is essential for proHB-EGF-induced apoptosis. From these results, we concluded that proHB-EGF has unique biological activity through cell-cell contact which is distinct from the activity of sHB-EGF (on submitting).
2)Analysis of the mechanism of the ectodomain shedding of proHB-EGF The ectodomains of many proteins located at the cell surface are shed upon cell stimulation. One such protein is HB-EGF that exists in a membrane-anchored form which is converted to a soluble form upon cellstimulation with TPA, an activator of PKC.We found that PKCdelta binds in vivo and in vitro to the cytoplasmic domain of MDC9/meltrin-gamma/ADAM9, a member of the metalloprotease-disintegrin family. Furthermore, the presence of constitutively active PKCdelta or MDC9 results in the shedding of the ectodomain of proHB-EGF, whereas MDC9 mutants lacking the metalloprotease domain, as well as kinase-negative PKCdelta suppress the TPA-induced shedding of the ectodomain. These results suggest that MDC9 and PKCdelta are involved in the stimulus-coupled shedding of the ptoFLB-EGF ectodomain (EMBO J., 17, 7260-, 1998).
3)Identification of novel components of proHB-EGF complex To identify the novel protein(s) associated with proHB-EGF, we preapred several monoclonal antibodies that recognize molecule which is co-precipitated with proHB-EGF by diphtheria toxin (DT). Among them, mAblC9-2 recognizes its antigen that is co-precipitated with proHB-EGF and CD9 specifically by DT, but not by anti-HB-EGF antibody, suggesting that association of proHB-EGF and 1C9-2 antigen molecule is physiological because DT can bind to only proHB-EGF which forms a complex with CD9 while anti-HB-EGF antibody can bind all population of proHB-EGF.Now we are undergoing identification and purification of the 1C9-2 antigen molecule. Less
|
Research Products
(3 results)
-
-
-
[Publications] Izumi, Y., Hirata, M., Hasuwa, H., Iwamoto.R., Umata, T., Miyado, K., Tamai, Y., Kurisaki, T., Sehara-Fujisawa, A., Ohno, S.and Mekada, E.: "A metalloprotease-disintegrin, MDC9/Meltrin-g/ADAM9, and PKCd are involved in TPA-induced ectodomain shedding of membrane anchored heparin-binding EGF-like growth factor." EMBO J.17. 7260-7272 (1998)
Description
「研究成果報告書概要(欧文)」より
