Quantitative Proteomics Analysis Reveals the Min System of Escherichia coli Modulates Reversible Protein Association with the Inner Membrane

Abstract

The Min system of Escherichia coli mediates placement of the division septum at the midcell. It oscillates from pole to pole to establish a concentration gradient of the division inhibition that is high at the poles but low at the midcell; the cell middle thereby becomes the most favorable site for division. Although Min oscillation is well studied from molecular and biophysical perspectives, it is still an enigma as to whether such a continuous, energy-consuming, and organized movement of the Min proteins would affect cellular processes other than the division site selection. To tackle this question, we compared the inner membrane proteome of the wild-type and Δmin strains using a quantitative approach. Forty proteins that showed differential abundance on the inner membrane of the mutant cells were identified and defined as proteins of interest (POIs). More than half of the POIs were peripheral membrane proteins, suggesting that the Min system affects mainly reversible protein association with the inner membrane. In addition, 6 out of 10 selected POIs directly interacted with at least one of the Min proteins, confirming the correlation between POIs and the Min system.Further analysis revealed a functional relationship between metabolism and the Min system. Metabolic enzymes accounted for 45% of the POIs, and there was a change of metabolites in the related reactions. We hypothesize that the Min system could alter the membrane location of proteins to modulate their enzymatic activity. Thus, the metabolic modulation in the Δmin mutant is likely an adaptive phenotype in cells of abnormal size and chromosome number due to an imbalanced abundance of proteins on the inner membrane. Taken together, the current work reports novel interactions of the Min system and reveals a global physiological impact of the Min system in addition to the division site placement.

The bacterial DNA binding protein MatP involved in linking the nucleoid terminal domain to the divisome at midcell interacts with lipid membranes

“…5 ). The subsequent release from the membrane to bind again the mat S sites might be assisted by the oscillation behaviour of MinD that displaces proteins from the membrane surface of the new poles (32, 33). It is well known that the Min system oscillates between the old poles and the newly formed septum before the daughter cells have separated (34).…”

Mapping out Min protein patterns in fully confined fluidic chambers

“…For example, MinD increased the order of the lipids and decreased their mobility in inverted inner E. coli membranes that contained integral proteins more than it does in synthetic vesicles that are purely lipidic (Mazor et al, 2008). Similarly, the Min system affects the association of inner-membrane peripheral proteins and interacts with some of them directly (Lee et al, 2016). It is thus possible that a yet unidentified protein species is needed in order to reproduce the in vivo geometrical selection rules of the Min system in an in vitro environment.…”

Structural insights into the interaction between phytoplasmal effector causing phyllody 1 and MADS transcription factors

“…The bands containing the crosslinked PHYL1 PnWB and SEP3_K proteins were cut from the SDS-PAGE and subjected to in-gel digestion with trypsin, Asp-N and trypsin/lysine C. The digested peptide mixtures were subjected to a nanoLC-nanoESI-MS/MS analysis (LTQ-Orbitrap Elite) using the standard protocol of the Academia Sinica common mass spectrometry facilities of the Institute of Biological Chemistry (Lee et al, 2016;Naveen and Hsiao, 2016). Finally, all data were analyzed using MASSMATRIX software (Xu and Freitas, 2009).…”