In:
Cancer Research, American Association for Cancer Research (AACR), Vol. 72, No. 8_Supplement ( 2012-04-15), p. 4006-4006
Abstract:
Background & aims: KITENIN (KAI1 C-terminal interacting tetraspanin) is not only a membrane-associated protein but also a functional protein promoting the invasiveness of colorectal cancer (CRC) cells. Recent studies about the mechanism of KITENIN function in the CRC cells indicate that KITENIN plays a pivotal role in tumor initiation and promotion through activating the activator protein-1 (AP-1) signaling. However, the contribution of each functional domain of KITENIN to AP-1 signaling is still unknown and the biochemical properties of C-terminal region of KITENIN were investigated. Methods: To compare the biochemical and functional properties of KITENIN deletion mutants with wild-type KITENIN, the various mutant constructs of C-terminal region (238-512 aa) were generated and being expressed in the 293T and Caco2 cells. AP-1 activity was measured via AP-1 luciferase reporter assays, and the cellular phenotypes of these cells expressing KITENIN mutants were examined via in vitro cell invasion and wound-healing assays. Results: KITENIN mutant with deletion of C-terminal 63 amino acids (DCKIT) markedly increased the AP-1 activity in contrast to other deletion mutants and wild-type KITENIN. Also, DCKIT increased the degradation of Dvl2 and stability of c-Jun, which are responsible for AP-1 activation by KITENIN. The C-terminal fragment of KITENIN (KICD, roughly 30 kDa) was generated and preferentially translocated to the nucleus after PMA treatment, but its functional significance is under investigation. A mutant construct of 408ALRA411-KITENIN was obtained by mutation of YXXΨ motifs, which directs the clathrin-dependent endocytosis of membrane-spanning proteins. This mutation did not influence the AP-1 activity, cell invasiveness, and cell migration by KITENIN but disrupted the interaction of KITENIN with Dvl2. Moreover, co-expression of this mutant with ErbB4 exhibited more attenuated AP-1 activity than that of forced expression of wild-type KITENIN and ErbB4. These results indicate that endocytosis of KITENIN and subsequent interaction with Dvl2 is essential to activating AP-1 signal and modulating cell motility by KITENIN. Conclusion: These biochemical properties of deletion mutants of KITENIN suggest that the C-terminal region of KITENIN is an important component for modulating AP-1 signal and CRC cell motility by KITENIN. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 4006. doi:1538-7445.AM2012-4006
Type of Medium:
Online Resource
ISSN:
0008-5472
,
1538-7445
DOI:
10.1158/1538-7445.AM2012-4006
Language:
English
Publisher:
American Association for Cancer Research (AACR)
Publication Date:
2012
detail.hit.zdb_id:
2036785-5
detail.hit.zdb_id:
1432-1
detail.hit.zdb_id:
410466-3
