Description
Cyclins and cyclin-dependent kinases (cdks) are evolutionarily conserved proteins that are essential for cell-cycle control in eukaryotes. Cyclins (regulatory subunits) bind to cdks (catalytic subunits) to form complexes that regulate the progression of the cell cycle. These complexes are regulated by activating and inhibitory phosphorylation events, as well as by interactions with small proteins that bind to cyclins, cdks, or cyclin-cdk complexes. These include p15, p16, p18, p19, p21 and p27 [Kip1]. p27 [Kip1] has been shown to inhibit the activity of multiple cyclin-cdk complexes, including cyclin D-cdk4, cyclin E-cdk2 and cyclin A-cdk2. p27 [Kip1] is a 27 kD protein which shares N-terminal sequence homology with p21, and like p21, p27 [Kip1] contains a nuclear localization signal in its C-terminal region. IL-2 activation of T cells has been reported to lead to a decrease in p27 [Kip1] and entry into S phase. Removal of IL-2 from T cell cultures results in increased levels of p27 [Kip1] and cell quiescence.
Bioimaging 1. Seed the cells in appropriate culture medium at ~10,000 cells per well in a BD Falcon™ 96-well Imaging Plate (Cat. No. 353219) and culture overnight. 2. Remove the culture medium from the wells, and fix the cells by adding 100 μl of BD Cytofix™ Fixation Buffer (Cat. No. 554655) to each well. Incubate for 10 minutes at room temperature (RT). 3. Remove the fixative from the wells, and permeabilize the cells using either BD Perm Buffer III, 90% methanol, or Triton™ X-100: a. Add 100 μl of -20°C 90% methanol or Perm Buffer III (Cat. No. 558050) to each well and incubate for 5 minutes at RT. OR b. Add 100 μl of 0.1% Triton™ X-100 to each well and incubate for 5 minutes at RT. 4. Remove the permeabilization buffer, and wash the wells twice with 100 μl of 1× PBS. 5. Remove the PBS, and block the cells by adding 100 μl of BD Pharmingen™ Stain Buffer (FBS) (Cat. No. 554656) to each well. Incubate for 30 minutes at RT. 6. Remove the blocking buffer and add 50 μl of the optimally titrated primary antibody (diluted in Stain Buffer) to each well, and incubate for 1 hour at RT. 7. Remove the primary antibody, and wash the wells three times with 100 μl of 1× PBS. 8. Remove the PBS, and add the second step reagent at its optimally titrated concentration in 50 μl to each well, and incubate in the dark for 1 hour at RT. 9. Remove the second step reagent, and wash the wells three times with 100 μl of 1× PBS. 10. Remove the PBS, and counter-stain the nuclei by adding 200 μl per well of 2 μg/ml Hoechst 33342 (e.g., Sigma-Aldrich Cat. No. B2261) in 1× PBS to each well at least 15 minutes before imaging. 11. View and analyze the cells on an appropriate imaging instrument. Bioimaging: For more detailed information please refer to http://www.bdbiosciences.com/support/resources/protocols/ceritifed_reagents.jsp Western blot: For more detailed information please refer to http://www.bdbiosciences.com/pharmingen/protocols/Western_Blotting.shtml
Store undiluted at 4°C. The monoclonal antibody was purified from tissue culture supernatant or ascites by affinity chromatography.
1. Since applications vary, each investigator should titrate the reagent to obtain optimal results.
2. Please refer to www.bdbiosciences.com/us/s/resources for technical protocols.
3. Caution: Sodium azide yields highly toxic hydrazoic acid under acidic conditions. Dilute azide compounds in running water before discarding to avoid accumulation of potentially explosive deposits in plumbing.
4. This antibody has been developed and certified for the bioimaging application. However, a routine bioimaging test is not performed on every lot. Researchers are encouraged to titrate the reagent for optimal performance.
5. Triton is a trademark of the Dow Chemical Company.
