Cell Signaling Technology

Product Pathways - Apoptosis / Autophagy

SignalSilence® Bim siRNA #6461

Western Blotting

Western Blotting

Western blot analysis of extracts from MCF-7 cells 48 hours following mock transfection, transfection with nonspecific (control) siRNA or transfection with Bim siRNA. Bim was detected using Bim Antibody #4582, and p42 was detected using p42 MAPK Antibody #9108. The Bim Antibody confirms silencing of Bim expression, and the p42 MAPK Antibody is used to control for protein loading and siRNA specificity.

Fluorescent Detection

Fluorescent Detection

Fluorescent detection of SignalSilence® Control siRNA (Fluorescein Conjugate) #6201 in living HeLa cells 24 hours post-transfection, demonstrating nearly 100% transfection efficiency.

Directions for Use

CST recommends transfection with 100 nM Bim siRNA. Decreased Bim expression was observed 24-72 hours post-transfection. See Protocol for transfection procedure.

Background

Bim/Bod is a pro-apoptotic protein belonging to the BH3-only group of Bcl-2 family members including Bad, Bid, Bik, Hrk and Noxa that contain a BH3 domain but lack other conserved BH1 or BH2 domains (1,2). Bim induces apoptosis by binding to and antagonizing anti-apoptotic members of the Bcl-2 family. Interactions have been observed with Bcl-2, Bcl-xL, Mcl-1, Bcl-w, Bfl-1 and BHRF-1 (1,2). Bim functions in regulating apoptosis associated with thymocyte negative selection and following growth factor withdrawal, during which Bim expression is elevated (3-6). Three major isoforms of Bim are generated by alternative splicing: BimEL, BimL and BimS (1). The shortest form, BimS, is the most cytotoxic and is generally only transiently expressed during apoptosis. The BimEL and BimL isoforms may be sequestered to the dynein motor complex through an interaction with the dynein light chain and released from this complex during apoptosis (7). Apoptotic activity of these longer isoforms may be regulated by phosphorylation (8,9). Environmental stress triggers Bim phosphorylation by JNK and results in its dissociation from the dynein complex and increased apoptotic activity.

Previous studies have shown that silencing of Bim using siRNA can reduce paclitaxel-induced apoptosis (8).

  1. O'Connor, L. et al. (1998) EMBO J 17, 384-95.
  2. Hsu, S.Y. et al. (1998) Mol Endocrinol 12, 1432-40.
  3. Bouillet, P. et al. (2002) Nature 415, 922-6.
  4. Whitfield, J. et al. (2001) Neuron 29, 629-43.
  5. Dijkers, P.F. et al. (2000) Curr Biol 10, 1201-4.
  6. Ley, R. et al. (2003) J Biol Chem 278, 18811-6.
  7. Puthalakath, H. et al. (1999) Mol Cell 3, 287-96.
  8. Lei, K. and Davis, R.J. (2003) Proc Natl Acad Sci U S A 100, 2432-7.
  9. Putcha, G.V. et al. (2003) Neuron 38, 899-914.
  10. Sunters, A. et al. (2003) J. Biol. Chem. 278, 49797-49805.

Application References

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Companion Products

Limited Use Label License, RNA interference: This product is licensed under European Patent 1144623 and foreign equivalents from Ribopharma AG, Kulmbach, Germany and is provided only for use in non-commercial research specifically excluding use (a) in drug discovery or drug development, including target identification or target validation, by or on behalf of a commercial entity, (b) for contract research or commercial screening services, (c) for the production or manufacture of siRNA-related products for sale, or (d) for the generation of commercial databases for sale to Third Parties. Information about licenses for these and other commercial uses is available from Ribopharma AG, Fritz-Hornschuch-Str. 9, D-95326 Kulmbach, Germany.

This product is for in vitro research use only and is not intended for use in humans or animals. This product is not intended for use as therapeutic or in diagnostic procedures.

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