Influence of Multiplicative Stochastic Variation on Translational Elongation Rates

TL;DR

This paper investigates how stochastic fluctuations in translation elongation rates cause multiplicative noise, leading to log-normal distribution of protein abundances and contributing significantly to extrinsic noise in biological systems.

Contribution

It provides a detailed analysis of translational noise from elongation rate fluctuations, revealing a natural extension of the Poisson distribution applicable to multiplicative noise.

Findings

Protein abundances follow a log-normal distribution due to multiplicative noise.

Elongation rate variability accounts for a major component of extrinsic noise.

The analysis introduces a broad applicability distribution for multiplicative noise processes.

Abstract

Recent experiments have shown that stochastic effects exerted at the level of translation contribute a substantial portion of the variation in abundance of proteins expressed at moderate to high levels. This study analyzes translational noise arising from fluctuations in residue-specific elongation rates. The resulting variation has multiplicative components that lead individual protein abundances in a population to exhibit approximately log-normal behavior. The high variability inherent in the process leads to parameter variation that has the features of a type of noise in biological systems that has been characterized as extrinsic. Elongation rate variation offers an accounting for a major component of extrinsic noise, and the analysis provided here highlights a probability distribution that is a natural extension of the Poisson and has broad applicability to many types of multiplicative noise processes.