Effects of multimerization on the temporal variability of protein complex abundance

Abstract

We explore whether the process of multimerization can be used as a means to regulate noise in the abundance of functional protein complexes. Additionally, we analyze how this process affects the mean level of these functional units, response time of a gene, and temporal correlation between the numbers of expressed proteins and of the functional multimers. We show that, although multimerization increases noise by reducing the mean number of functional complexes it can reduce noise in comparison with a monomer, when abundance of the functional proteins are comparable. Alternatively, reduction in noise occurs if both monomeric and multimeric forms of the protein are functional. Moreover, we find that multimerization either increases the response time to external signals or decreases the correlation between number of functional complexes and protein production kinetics. Finally, we show that the results are in agreement with recent genome-wide assessments of cell-to-cell variability in protein numbers and of multimerization in essential and non-essential genes in Escherichia coli, and that the effects of multimerization are tangible at the level of genetic circuits.

Noise Analysis in Biochemical Complex Formation

“…Note that in this case x ss is equal to y ss , while r = γ x /γ z . A close examination of (15) shows that it resembles (12) except for some scaling factors. Not surprisingly, even in this case varying S x produces a non-monotonic, U -shape behavior for noise in Z (we do not show the results here).…”

“…However, many species are present at low copy numbers in cells, and thereby stochasticity (or noise) in the reactions involving them is unavoidable [12]. Previous work indeed has shown that complex formation might be an important mechanism in control of noise in gene regulation [13][14][15].…”

CyDiv, a Conserved and Novel Filamentous Cyanobacterial Cell Division Protein Involved in Septum Localization

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InCoB2013 introduces Systems Biology as a major conference theme

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