BCL-XL-dependent light scattering by apoptotic cells

Nada N. Boustany, Yien Che Tsai, Bryan Pfister, Wilsaan Joiner, George A. Oyler, Nitish V. Thakor

Research output: Contribution to journalArticle

40 Scopus citations

Abstract

We measured the intensity ratio of wide-to-narrow angle scatter, optical scatter image ratio (OSIR), in single cells during apoptosis and after overexpression of the mitochondria-bound antiapoptotic protein BCL-X L. OSIR is sensitive to particle size/shape for objects with wavelength-scale dimensions, and was used as a morphometric measure of cellular response. Three cell variants were treated with staurosporine (STS): nontransfected parental CSM14.1, CSM14.1 stably expressing yellow fluorescent protein (YFP) with diffuse YFP fluorescence, and apoptosis-resistant CSM14.1 stably expressing the fusion protein construct YFP-BCL-XL with YFP fluorescence localized on the mitochondria. After treatment with 1 or 2 μM STS, the measured OSIR decreased monotonically by ∼25% in the nontransfected and YFP variants, and reached a steady-state value 40-60 min after STS treatment. The decrease in OSIR at the onset of apoptosis preceded phosphatidyl serine exposure by 5 h. In the YFP-BCL-XL cell variant, the initial OSIR was already ∼24% lower than the initial OSIR in YFP and nontransfected cells, and only decreased by <10% after STS treatment. Alterations in light scattering by cells overexpressing BCL-XL even before apoptosis induction raise interesting questions as to the role of BCL-XL in conferring apoptosis resistance by preconditioning the cells and possibly altering mitochondrial morphology.

Original languageEnglish (US)
Pages (from-to)4163-4171
Number of pages9
JournalBiophysical Journal
Volume87
Issue number6
DOIs
StatePublished - Jan 1 2004
Externally publishedYes

ASJC Scopus subject areas

  • Biophysics

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    Boustany, N. N., Tsai, Y. C., Pfister, B., Joiner, W., Oyler, G. A., & Thakor, N. V. (2004). BCL-XL-dependent light scattering by apoptotic cells. Biophysical Journal, 87(6), 4163-4171. https://doi.org/10.1529/biophysj.104.048736