Role of spectral counting in quantitative proteomics.
Spectral count, defined as the total number of spectra identified for a protein, has gained acceptance as a practical, label-free, semiquantitative measure of protein abundance in proteomic studies. In this review, we discuss issues affecting the performance of spectral counting relative to other label-free methods, as well as its limitations. Possible consequences of modifications, which are commonly applied to raw spectral counts to improve abundance estimations, are considered. The use of spectral counting for different types of quantitation studies is explored and critiqued. Different statistical methods and underlying frameworks that have been applied to spectral count analysis are described and compared, and problem areas that undermine confident statistical analysis are considered. Finally, the issue of accurate estimation of false-discovery rates is addressed and identified as a major current challenge in quantitative proteomics.
Lundgren
Deborah H
DH
Department of Cell Biology and Center for Vascular Biology, University of Connecticut Health Center, 263 Farmington Avenue, Farmington, CT 06030, USA.
Hwang
Sun-Il
SI
Wu
Linfeng
L
Han
David K
DK
D030562:Databases, Protein; D013058:Mass Spectrometry / Q000706:statistics & numerical data*; D015233:Models, Statistical; D040901:Proteomics / Q000379:methods* / Q000592:standards; D013057:Spectrum Analysis / Q000706:statistics & numerical data