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p27 KIP 1 Rabbit mAb

Catalog No.: F2538

Lane 1: HCT 116
Lane 2: HCT 116 (KO CDKN1B)
Lane 3: HeLa
Lane 4: MCF7

Experiment Essentials

Subcellular Location: Cytoplasm, Endosome, Nucleus.
WB
Recommending using RIPA/NP-40 Lysis Buffer to prepare lysates.
Recommended wet transfer conditions: 200 mA, 60 min.
Recommended primary antibody dilution ratio 1:5000.

Usage Information

Dilution
WB1:5000 IP1:500 IHC1:50 IF1:100 FCM1:200

Application
WB, IP, IHC, IF, FCM

Source
Rabbit

Reactivity
Human, Mouse, Rat

Storage Buffer
PBS, pH 7.2+50% Glycerol+0.05% BSA+0.01% NaN3

Storage (from the date of receipt)
-20°C (avoid freeze-thaw cycles), 2 years

Predicted MW
22 kDa

Exprimental Methods

WB
Experimental Protocol: Sample preparation 1. Tissue: Lyse the tissue sample by adding an appropriate volume of ice-cold RIPA/NP-40 Lysis Buffer (containing Protease Inhibitor Cocktail)，and homogenize the tissue at a low temperature or lyse it by sonication on ice, then incubate on ice for 30 minutes. 2. Adherent cell: Aspirate the culture medium and transfer the cells into an EP tube. Wash the cells with ice-cold PBS twice. Add an appropriate volume of RIPA/NP-40 Lysis Buffer (containing Protease Inhibitor Cocktail), sonicate to lyse the cells, and incubate on ice for 30 minutes. 3. Suspension cell: Transfer the culture medium to a pre-cooled centrifuge tube. Centrifuge and aspirate the supernatant. Wash the cells with ice-cold PBS twice.Add an appropriate volume of RIPA/NP-40 Lysis Buffer (containing Protease Inhibitor Cocktail), sonicate to lyse the cells, and incubate on ice for 30 minutes. 4. Place the lysate into a pre-cooled microcentrifuge tube. Centrifuge at 4°C for 15 min. Collect the supernatant; 5. Remove a small volume of lysate to determine the protein concentration; 6. Combine the lysate with protein loading buffer. Boil 20 µL sample under 95-100°C for 5 min. Centrifuge for 5 min after cool down on ice. Electrophoretic separation 1. According to the concentration of extracted protein, load appropriate amount of protein sample and marker onto SDS-PAGE gels for electrophoresis. Recommended separating gel (lower gel) concentration: 10%. Reference Table for Selecting SDS-PAGE Separation Gel Concentrations 2. Power up 80V for 30 minutes. Then the power supply is adjusted (110 V~150 V), the Marker is observed, and the electrophoresis can be stopped when the indicator band of the predyed protein Marker where the protein is located is properly separated. (Note that the current should not be too large when electrophoresis, too large current (more than 150 mA) will cause the temperature to rise, affecting the result of running glue. If high currents cannot be avoided, an ice bath can be used to cool the bath.) Transfer membrane 1. Take out the converter, soak the clip and consumables in the pre-cooled converter; 2. Activate PVDF membrane with methanol for 1 min and rinse with transfer buffer; 3. Install it in the order of "black edge of clip - sponge - filter paper - filter paper - glue -PVDF membrane - filter paper - filter paper - sponge - white edge of clip"; 4. The protein was electrotransferred to PVDF membrane. ( 0.45 µm PVDF membrane is recommended ) Reference Table for Selecting PVDF Membrane Pore Size Specifications Recommended conditions for wet transfer: 200 mA, 60 min. ( Note that the transfer conditions can be adjusted according to the protein size. For high-molecular-weight proteins, a higher current and longer transfer time are recommended. However, ensure that the transfer tank remains at a low temperature to prevent gel melting.) Block 1. After electrotransfer, wash the film with TBST at room temperature for 5 minutes; 2. Incubate the film in the blocking solution for 1 hour at room temperature; 3. Wash the film with TBST for 3 times, 5 minutes each time. Antibody incubation 1. Use 5% skim milk powder to prepare the primary antibody working liquid (recommended dilution ratio for primary antibody 1:5000), gently shake and incubate with the film at 4°C overnight; 2. Wash the film with TBST 3 times, 5 minutes each time; 3. Add the secondary antibody to the blocking solution and incubate with the film gently at room temperature for 1 hour; 4. After incubation, wash the film with TBST 3 times for 5 minutes each time. Antibody staining 1389. Add the prepared ECL luminescent substrate (or select other color developing substrate according to the second antibody) and mix evenly; 2. Incubate with the film for 1 minute, remove excess substrate (keep the film moist), wrap with plastic film, and expose in the imaging system.

Experimental Protocol:

Sample preparation

1. Tissue: Lyse the tissue sample by adding an appropriate volume of ice-cold RIPA/NP-40 Lysis Buffer (containing Protease Inhibitor Cocktail)，and homogenize the tissue at a low temperature or lyse it by sonication on ice, then incubate on ice for 30 minutes.

2. Adherent cell: Aspirate the culture medium and transfer the cells into an EP tube. Wash the cells with ice-cold PBS twice. Add an appropriate volume of RIPA/NP-40 Lysis Buffer (containing Protease Inhibitor Cocktail), sonicate to lyse the cells, and incubate on ice for 30 minutes.

3. Suspension cell: Transfer the culture medium to a pre-cooled centrifuge tube. Centrifuge and aspirate the supernatant. Wash the cells with ice-cold PBS twice.Add an appropriate volume of RIPA/NP-40 Lysis Buffer (containing Protease Inhibitor Cocktail), sonicate to lyse the cells, and incubate on ice for 30 minutes.

4. Place the lysate into a pre-cooled microcentrifuge tube. Centrifuge at 4°C for 15 min. Collect the supernatant;

5. Remove a small volume of lysate to determine the protein concentration;

6. Combine the lysate with protein loading buffer. Boil 20 µL sample under 95-100°C for 5 min. Centrifuge for 5 min after cool down on ice.

Electrophoretic separation

1. According to the concentration of extracted protein, load appropriate amount of protein sample and marker onto SDS-PAGE gels for electrophoresis. Recommended separating gel (lower gel) concentration: 10%. Reference Table for Selecting SDS-PAGE Separation Gel Concentrations

2. Power up 80V for 30 minutes. Then the power supply is adjusted (110 V~150 V), the Marker is observed, and the electrophoresis can be stopped when the indicator band of the predyed protein Marker where the protein is located is properly separated. (Note that the current should not be too large when electrophoresis, too large current (more than 150 mA) will cause the temperature to rise, affecting the result of running glue. If high currents cannot be avoided, an ice bath can be used to cool the bath.)

Transfer membrane

1. Take out the converter, soak the clip and consumables in the pre-cooled converter;

2. Activate PVDF membrane with methanol for 1 min and rinse with transfer buffer;

3. Install it in the order of "black edge of clip - sponge - filter paper - filter paper - glue -PVDF membrane - filter paper - filter paper - sponge - white edge of clip";

4. The protein was electrotransferred to PVDF membrane. ( 0.45 µm PVDF membrane is recommended ) Reference Table for Selecting PVDF Membrane Pore Size Specifications

Recommended conditions for wet transfer: 200 mA, 60 min.

( Note that the transfer conditions can be adjusted according to the protein size. For high-molecular-weight proteins, a higher current and longer transfer time are recommended. However, ensure that the transfer tank remains at a low temperature to prevent gel melting.)

Block

1. After electrotransfer, wash the film with TBST at room temperature for 5 minutes;

2. Incubate the film in the blocking solution for 1 hour at room temperature;

3. Wash the film with TBST for 3 times, 5 minutes each time.

Antibody incubation

1. Use 5% skim milk powder to prepare the primary antibody working liquid (recommended dilution ratio for primary antibody 1:5000), gently shake and incubate with the film at 4°C overnight;

2. Wash the film with TBST 3 times, 5 minutes each time;

3. Add the secondary antibody to the blocking solution and incubate with the film gently at room temperature for 1 hour;

4. After incubation, wash the film with TBST 3 times for 5 minutes each time.

Antibody staining

1389. Add the prepared ECL luminescent substrate (or select other color developing substrate according to the second antibody) and mix evenly;

2. Incubate with the film for 1 minute, remove excess substrate (keep the film moist), wrap with plastic film, and expose in the imaging system.

Datasheet & SDS

Biological Description

Specificity
p27 KIP 1 Rabbit mAb recognizes endogenous levels of total p27 KIP 1 protein.

Synonym(s)
CDKN1B/Kip1 p27,p27,p27 KIP 1

Clone
A16H11

Background
p27 KIP 1 is a cyclin-dependent kinase inhibitor (CDKI) that plays a pivotal role in regulating the cell cycle, particularly during the G1 phase, by inhibiting cyclin-CDK complexes such as cyclin E-CDK2 and cyclin D-CDK4/6. p27 is an intrinsically disordered protein (IDP) with an N-terminal domain that binds cyclin-CDK complexes, a central region mediating protein-protein interactions, and a C-terminal domain subject to post-translational modifications. By binding to these cyclin-CDK complexes, p27 prevents their activation, halting the transition from the G1 to S phase and controlling cell proliferation. p27 is regulated through post-translational modifications, including phosphorylation, ubiquitination, and acetylation, which influence its stability, localization, and activity. Phosphorylation at Thr187 by cyclin E-CDK2 triggers p27’s degradation via the SCF^Skp2 ubiquitin ligase complex, a key regulatory mechanism. Additionally, tyrosine phosphorylation (e.g., at Tyr88 and Tyr74) can modulate p27’s inhibitory function or convert it into a partial activator of CDKs. The stability of p27 is also influenced by epigenetic factors such as methylation of its gene, which can suppress its expression. Loss or reduced expression of p27 correlates with increased tumor aggressiveness and poor prognosis in various cancers.

Background

p27 KIP 1 is a cyclin-dependent kinase inhibitor (CDKI) that plays a pivotal role in regulating the cell cycle, particularly during the G1 phase, by inhibiting cyclin-CDK complexes such as cyclin E-CDK2 and cyclin D-CDK4/6. p27 is an intrinsically disordered protein (IDP) with an N-terminal domain that binds cyclin-CDK complexes, a central region mediating protein-protein interactions, and a C-terminal domain subject to post-translational modifications. By binding to these cyclin-CDK complexes, p27 prevents their activation, halting the transition from the G1 to S phase and controlling cell proliferation. p27 is regulated through post-translational modifications, including phosphorylation, ubiquitination, and acetylation, which influence its stability, localization, and activity. Phosphorylation at Thr187 by cyclin E-CDK2 triggers p27’s degradation via the SCF^Skp2 ubiquitin ligase complex, a key regulatory mechanism. Additionally, tyrosine phosphorylation (e.g., at Tyr88 and Tyr74) can modulate p27’s inhibitory function or convert it into a partial activator of CDKs. The stability of p27 is also influenced by epigenetic factors such as methylation of its gene, which can suppress its expression. Loss or reduced expression of p27 correlates with increased tumor aggressiveness and poor prognosis in various cancers.

References
[1] Lloyd RV, et al. Am J Pathol. 1999 Feb;154(2):313-23. [2] Ou L, et al. ACS Chem Biol. 2012 Apr 20;7(4):678-82.

Reference Table for Selecting PVDF Membrane Pore Size Specifications

Protein Size (kDa)	PVDF Transfer Membrane Pore Size (μm)
< 10	0.22
10-20	0.22
20-30	0.45
30-45	0.45
45-70	0.45
80-100	0.45
100-140	0.45
> 140	0.45

Tech Support

Answers to questions you may have can be found in the inhibitor handling instructions. Topics include how to prepare stock solutions, how to store inhibitors, and issues that need special attention for cell-based assays and animal experiments.

Handling Instructions

Tel: +1-832-582-8158 Ext:3
If you have any other enquiries, please leave a message.

* Indicates a Required Field

Protein Size (kDa)	Separating Gel Percentage
4-40	20%
12-45	15%
10-70	12.5%
15-100	10%
25-100	8%
60-210	5%