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Estimated in vivo activities and copy number of molecules involved in MHC class-I-antigen presentation

Range	Table - link
Organism	vertebrates
Reference	Yewdell JW, Reits E, Neefjes J. Making sense of mass destruction: quantitating MHC class I antigen presentation. Nat Rev Immunol. 2003 Dec3(12):952-61. DOI: 10.1038/nri1250 p.958 table 2PubMed ID14647477
Primary Source	[7] Reits, E. et al. Peptide diffusion, protection, and degradation in nuclear and cytoplasmic compartments before antigen presentation by MHC class I. Immunity 18, 97–108 (2003) [10] Neefjes, J. J., Momburg, F. & Hammerling, G. J. Selective and ATP-dependent translocation of peptides by the MHCencoded transporter. Science 261, 769–771 (1993) [66] Princiotta, M. F. et al. Quantitating protein synthesis, degradation, and endogenous antigen processing. Immunity 18, 343–354 (2003) [91] Gakamsky, D. M., Davis, D. M., Strominger, J. L. & Pecht, I. Assembly and dissociation of human leukocyte antigen (HLA)-A2 studied by real-time fluorescence resonance energy transfer. Biochemistry 39, 11163–11169 (2000)PubMed ID12530979, 8342042, 12648452, 10998256
Method	Primary source [7] abstract: "[Investigators] have visualized the fate and dynamics of intracellular peptides in living cells." Primary source [66] abstract: "Using L929 cells [mouse], [investigators] quantitated the macroeconomics of protein synthesis and degradation and the microeconomics of producing MHC class I associated peptides from viral translation products." Primary source [91] abstract: "Peptide affinity and kinetics of the ternary complex formation and dissociation were investigated in real time by monitoring the fluorescence resonance energy transfer (FRET) from intrinsic HLA-A2 heavy-chain tryptophans to a dansyl fluorophore conjugated to the bound peptide."
Comments	P.959 left column 2nd paragraph: "While each ribosome is producing a protein every 90 seconds, each proteasome is degrading 2.25 substrates per minute. Proteasomes are probably not working at full capacity though. Two independent studies estimate that proteasomes are acting at ~20% of their total capacity in unstressed cells [refs 69, 70], indicating a Vmax of 11 substrates per proteasome per minute, or five seconds per substrate, which is 20 times faster than the rate of protein synthesis (see table 2 for kinetics)." See note beneath table
Entered by	Uri M
ID	113775