title: Universal protein fluctuations in populations of microorganisms.
abstract: The copy number of any protein fluctuates among cells in a population; characterizing and understanding these fluctuations is a fundamental problem in biophysics. We show here that protein distributions measured under a broad range of biological realizations collapse to a single non-gaussian curve under scaling by the first two moments. Moreover, in all experiments the variance is found to depend quadratically on the mean, showing that a single degree of freedom determines the entire distribution. Our results imply that protein fluctuations do not reflect any specific molecular or cellular mechanism, and suggest that some buffering process masks these details and induces universality.
authors.affiliation: Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA.
authors.forename: Hanna
authors.initials: H
authors.lastname: Salman
authors.forename: Naama
authors.initials: N
authors.lastname: Brenner
authors.forename: Chih-kuan
authors.initials: CK
authors.lastname: Tung
authors.forename: Noa
authors.initials: N
authors.lastname: Elyahu
authors.forename: Elad
authors.initials: E
authors.lastname: Stolovicki
authors.forename: Lindsay
authors.initials: L
authors.lastname: Moore
authors.forename: Albert
authors.initials: A
authors.lastname: Libchaber
authors.forename: Erez
authors.initials: E
authors.lastname: Braun
mesh_terms: D004926:Escherichia coli / Q000737:chemistry / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000737:chemistry / Q000378:metabolism*; D008954:Models, Biological; D012441:Saccharomyces cerevisiae / Q000737:chemistry / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry / Q000378:metabolism*
chemical_list: D029968:Escherichia coli Proteins; D029701:Saccharomyces cerevisiae Proteins