Cell Signaling Technology

Product Pathways - Neuroscience

SignalSilence® CDK5 siRNA I #6216

Applications Reactivity
Transfection H (M) (R)

Reactivity Key:  H=Human  M=Mouse  R=Rat
Species cross-reactivity is determined by western blot. Species enclosed in parentheses are predicted to react based on 100% sequence homology.

Western Blotting

Western Blotting

Western blot analysis of extracts from HeLa cells, transfected with 100 nM SignalSilence® Control siRNA (Unconjugated) #6568 (-), SignalSilence® CDK5 siRNA I (+) or SignalSilence® CDK5 siRNA II #6217 (+), using CDK5 Antibody #2506 (upper) or α-Tubulin (11H10) Rabbit mAb #2125 (lower). The CDK5 Antibody confirms silencing of CDK5 expression, while the α-Tubulin (11H10) Rabbit mAb is used to control for loading and specificity of CDK5 siRNA.

Description

SignalSilence® CDK5 siRNA I from Cell Signaling Technology (CST) allows the researcher to specifically inhibit CDK5 expression using RNA interference, a method whereby gene expression can be selectively silenced through the delivery of double stranded RNA molecules into the cell. All SignalSilence® siRNA products from CST are rigorously tested in-house and have been shown to reduce target protein expression by western analysis.

Quality Control

Oligonucleotide synthesis is monitored base by base through trityl analysis to ensure appropriate coupling efficiency. The oligo is subsequently purified by affinity-solid phase extraction. The annealed RNA duplex is further analyzed by mass spectrometry to verify the exact composition of the duplex. Each lot is compared to the previous lot by mass spectrometry to ensure maximum lot-to-lot consistency.

Directions for Use

CST recommends transfection with 100 nM CDK5 siRNA I 48 to 72 hours prior to cell lysis. For transfection procedure, follow protocol provided by the transfection reagent manufacturer. Please feel free to contact CST with any questions on use.

Each vial contains the equivalent of 100 transfections, which corresponds to a final siRNA concentration of 100 nM per transfection in a 24-well plate with a total volume of 300 μl per well.

Background

Cyclin-dependent kinases (CDKs) are serine/threonine kinases that are activated by cyclins and govern eukaryotic cell cycle progression. While CDK5 shares high sequence homology with its family members, it is thought mainly to function in postmitotic neurons to regulate the cytoarchitecture of these cells. Analogous to cyclins, the regulatory subunits p35 and p39 associate with and activate CDK5 despite the lack of sequence homology. CDK5 is ubiquitously expressed, with high levels of kinase activity detected primarily in the nervous system due to the narrow expression pattern of p35 and p39 in post-mitotic neurons. A large number of CDK5 substrates have been identified although no substrates have been specifically attributed to p35 or p39. Substrates of CDK5 include p35, PAK1, Src, β-catenin, tau, neurofilament-H, neurofilament-M, synapsin-1, APP, DARPP32, PP1-inhibitor, and Rb. p35 is rapidly degraded (T1/2 <20 min) by the ubiquitin-proteasome pathway (1). However, p35 stability increases as CDK5 kinase activity decreases, likely as a result of decreased phosphorylation of p35 at Thr138 by CDK5 (2). Proteolytic cleavage of p35 by calpain produces p25 upon neurotoxic insult, resulting in prolonged activation of CDK5 by p25. Research studies have shown accumulation of p25 in neurodegenerative diseases, such as Alzheimer's disease and amyotrophic lateral sclerosis (ALS) (3,4).

  1. Dhavan, R. and Tsai, L.H. (2001) Nat Rev Mol Cell Biol 2, 749-59.
  2. Patrick, G.N. et al. (1998) J Biol Chem 273, 24057-64.
  3. Lee, M.S. et al. (2000) Nature 405, 360-4.
  4. Kusakawa, G. et al. (2000) J Biol Chem 275, 17166-72.

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.

For Research Use Only. Not For Use In Diagnostic Procedures.

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