The role of the essential GTPase ObgE in regulating lipopolysaccharide synthesis in Escherichia coli

<p>Source data accompanying scientific publication.</p> <p>Abstract: <span>During growth, cells need to synthesize and expand their envelope, a process that requires careful regulation. Here, we show that the GTPase ObgE of <em>E. coli</em> contributes to the regulation of lipopolysaccharide (LPS) synthesis, an essential component of the Gram-negative outer membrane. Using a dominant-negative mutant (named &lsquo;ObgE*&rsquo;), we show a direct interaction between ObgE and LpxA, which catalyzes the first step in LPS synthesis. This interaction is enhanced by the mutation in ObgE* which, when bound to GTP, leads to inhibition of LpxA, decreased LPS synthesis, and cell death. Although wild-type ObgE does not exert the same strong effects as ObgE* on LpxA or LPS synthesis, our data indicate that ObgE participates in the regulation of cell envelope synthesis in <em>E. coli</em>. Because ObgE also influences other cellular functions (i.e., ribosome assembly, DNA replication, etc.), it seems increasingly plausible that this GTPase coordinates several processes to finetune cell growth.</span></p>