title: Protein standard absolute quantification (PSAQ) method for the measurement of cellular ubiquitin pools.
abstract: The protein ubiquitin is an important post-translational modifier that regulates a wide variety of biological processes. In cells, ubiquitin is apportioned among distinct pools, which include a variety of free and conjugated species. Although maintenance of a dynamic and complex equilibrium among ubiquitin pools is crucial for cell survival, the tools necessary to quantify each cellular ubiquitin pool have been limited. We have developed a quantitative mass spectrometry approach to measure cellular concentrations of ubiquitin species using isotope-labeled protein standards and applied it to characterize ubiquitin pools in cells and tissues. Our method is convenient, adaptable and should be a valuable tool to facilitate our understanding of this important signaling molecule.
authors: Department of Biology, Stanford University, Stanford, California, USA.
authors: Stephen E
authors: SE
authors: Kaiser
authors: Brigit E
authors: BE
authors: Riley
authors: Thomas A
authors: TA
authors: Shaler
authors: R Sean
authors: RS
authors: Trevino
authors: Christopher H
authors: CH
authors: Becker
authors: Howard
authors: H
authors: Schulman
authors: Ron R
authors: RR
authors: Kopito
mesh_terms: D000818:Animals; D006801:Humans; D007553:Isotope Labeling / Q000379:methods*; D013058:Mass Spectrometry / Q000379:methods* / Q000592:standards*; D013347:Subcellular Fractions / Q000378:metabolism*; D025801:Ubiquitin / Q000378:metabolism*; D014481:United States
chemical_list: D025801:Ubiquitin