Bax Inhibitor 1 Increases Cell Adhesion through Actin Polymerization: Involvement of Calcium and Actin Binding
SCIE
SCOPUS
- Title
- Bax Inhibitor 1 Increases Cell Adhesion through Actin Polymerization: Involvement of Calcium and Actin Binding
- Authors
- Lee, GH; Ahn, T; Kim, DS; Park, SJ; Lee, YC; Yoo, WH; Jung, SJ; Yang, JS; Kim, S; Muhlrad, A; Seo, YR; Chae, SW; Kim, HR; Chae, HJ
- Date Issued
- 2010-04-01
- Publisher
- AMER SOC MICROBIOLOGY
- Abstract
- Bax inhibitor 1 (BI-1), a transmembrane protein with Ca2+ channel-like activity, has antiapoptotic and anticancer activities. Cells overexpressing BI-1 demonstrated increased cell adhesion. Using a proteomics tool, we found that BI-1 interacted with gamma-actin via leucines 221 and 225 and could control actin polymerization and cell adhesion. Among BI-1(-/-) cells and cells transfected with BI-1 small interfering RNA (siRNA), levels of actin polymerization and cell adhesion were lower than those among BI-1(+/+) cells and cells transfected with nonspecific siRNA. BI-1 acts as a leaky Ca2+ channel, but mutations of the actin binding sites (L221A, L225A, and L221A/L225A) did not change intra-endoplasmic reticulum Ca2+, although deleting the C-terminal motif (EKDKKKEKK) did. However, store-operated Ca2+ entry (SOCE) is activated in cells expressing BI-1 but not in cells expressing actin binding site mutants, even those with the intact C-terminal motif. Consistently, actin polymerization and cell adhesion were inhibited among all the mutant cells. Compared to BI-1(+/+) cells, BI-1(-/-) cells inhibited SOCE, actin polymerization, and cell adhesion. Endogenous BI-1 knockdown cells showed a similar pattern. The C-terminal peptide of BI-1 (LMMLILAMNRKDKKKEKK) polymerized actin even after the deletion of four or six charged C-terminal residues. This indicates that the actin binding site containing L221 to D231 of BI-1 is responsible for actin interaction and that the C-terminal motif has only a supporting role. The intact C-terminal peptide also bundled actin and increased cell adhesion. The results of experiments with whole recombinant BI-1 reconstituted in membranes also coincide well with the results obtained with peptides. In summary, BI-1 increased actin polymerization and cell adhesion through Ca2+ regulation and actin interaction.
- URI
- https://oasis.postech.ac.kr/handle/2014.oak/11697
- DOI
- 10.1128/MCB.01357-09
- ISSN
- 0270-7306
- Article Type
- Article
- Citation
- MOLECULAR AND CELLULAR BIOLOGY, vol. 30, no. 7, page. 1800 - 1813, 2010-04-01
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