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Life Science > Proteomics > Recombinant Protein Expression > Protocols > Phosphorylation of Substrates
Proteomics & Protien Expression

Phosphorylation of Substrates

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Selected Protocol from "Protein-Protein Interactions", 2nd Edition, E. Golemis, P. Adam.

Phosphorylation of Substrates

Scott T. Eblin, N. Vinay Kumar and Michael J. Weber
Department of Microbiology and Cancer Center, Universtiy of Virginia Health System
Charlottesville, VA 22908


ABSTRACT
Ideally, one would like to be able to directly phosphorylate substrates in an intact cell. This could potentially be performed by introducing ATP analog into live or permeabilized cells. However, cells are impermeable to ATP, and the addition of labeled ATP analog to digitonin-permeabilized cells results in the hydrolysis of the analog ATP within 1 min (Chaudhary et al. 2002). Therefore, we have chosen to apply this technique to cell lysates or fractions. Here we describe two approaches to detect direct substrates of a protein kinase. The first approach involves identification of kinase-associated substrates by immunoprecipitating a tagged form of the mutant kinase from transfected COS-1 cells and performing a kinase reaction by the addition of [g-32P]ATP analog. The second approach involves the addition of recombinant mutant kinase and [g-32P]ATP analog to cell lysates. We have used these techniques for the phosphorylation of ERK2 substrates; however, this methodology can be applied to other protein kinases   Protein Protein Interactions

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Products Available for this Protocol
Protocol Material Description Product #  Product Name Add to Cart
Recombinant kinase C8482 Protein Kinase A catalytic subunit human, >90% (SDS-PAGE), recombinant, expressed in Escherichia coli, buffered aqueous glycerol solution
Sepharose CL-6B beads CL6B200 Sepharose® CL-6B, Cross-linked
SDS L4390 Sodium dodecyl sulfate, for molecular biology
PBS P5368 Phosphate buffered saline, pH 7.4, Biotechnology Performance Certified
Serum-free medium (DMEM) D6421 Dulbecco’s Modified Eagle’s Medium/Nutrient Mixture F-12 Ham, With 15 mM HEPES and sodium bicarbonate, without L-glutamine, liquid, sterile-filtered, cell culture tested
FLAG Peptide F3290 FLAG® Peptide, lyophilized powder
NaCl S3014 Sodium chloride, for molecular biology
2x Laemmli sample buffer S3401 Sample Buffer, Laemmli 2× Concentrate
20 mM HEPES (pH 7.4) 51558 HEPES buffered saline, BioChemika Ultra, for molecular biology, 2× concentrate
2mM EGTA E3889 Ethylene glycol-bis(2-aminoethylether)-N,N,N',N'-tetraacetic acid, for molecular biology
2mM MgCl2 M4880 Magnesium chloride
COS-1 cells 88031701 COS-1 Cell Line from African green monkey kidney, SV40 transformed

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