3T3-L1 Adipocyte Fractionation
Materials
- PBS
- Lysis Buffer (25 mM HEPES, 250 mM Sucrose, PI tablet)
- Optiprep
- Cool centrifuges and rotors for JA17/JA25.5, TLA100.3 and NVT90 to 4C
Fractionation
- Wash cells twice with ice cold PBS -/-
- Scrape 150 mm dish into 4 mL of Lysis Buffer
- Homogenize in Dounce Homogenizer 20X on ice
- Centrifuge 5 min at 3000g in JA17 or JA25.5 and collect post-nuclear supernatant (PNS). If desired resuspend pellet in 2 mL as mitochondria/nuclear fraction (MN)
- Centrifuge supernatant 15 min at 17 200g at 4C in JA17 or JA25.5 with brake off. Resuspend pellet in 2 mL as plasma membrane (PM). Save sample.
- Centrifuge supernatant 30 min at 48 000g at 4C in JA17 or JA25.5 with brake off. Resuspend pellet in 2 mL as high density microsomes (HDM). Save sample
- Centrifuge supernatant 75 min at 90 000 RPM in TLA 100.3 at 4C. Pellet is low density microsomes (LDM), supernatant is cytosol save a sample.
- To load equal volumes on a gel, load twice as much volume of PNS and cytosol as MN/PM/HDM/LDM.
Optiprep Gradient
- Wash LDM fraction once with lysis buffer and resuspend in 2 mL of lysis buffer. Save sample as LDM
- Gently homogenize 10X in Dounce Homogenizer
- Mix optiprep to generate 18% gradient (1.5 mL optiprep + 3.5 mL LDM)
- Centrifuge 4h at 62 000 RPM in NVT90 at 4C.
- Cut off top of tube and gently remove 350 uL fractions to fresh tubes on ice.
- Store samples at -80. Make up SDS samples and do not boil
References
<pubmed>17765682</pubmed>