Unfolded protein response-regulated Drosophila Fic (dFic) protein reversibly AMPylates BiP chaperone during endoplasmic reticulum homeostasis.

Drosophila Fic (dFic) mediates AMPylation, a covalent attachment of adenosine monophosphate (AMP) from ATP to hydroxyl side chains of protein substrates. Here, we identified the endoplasmic reticulum (ER) chaperone BiP as a substrate for dFic and mapped the modification site to Thr-366 within the ATPase domain. The level of AMPylated BiP in Drosophila S2 cells is high during homeostasis, whereas the level of AMPylated BiP decreases upon the accumulation of misfolded proteins in the ER.

AMPylation of Rho GTPases subverts multiple host signaling processes.

Rho GTPases are frequent targets of virulence factors as they are keystone signaling molecules. Herein, we demonstrate that AMPylation of Rho GTPases by VopS is a multifaceted virulence mechanism that counters several host immunity strategies. Activation of NFκB, Erk, and JNK kinase signaling pathways were inhibited in a VopS-dependent manner during infection with Vibrio parahaemolyticus.

Copper-catalyzed azide-alkyne cycloaddition (click chemistry)-based detection of global pathogen-host AMPylation on self-assembled human protein microarrays.

AMPylation (adenylylation) is a recently discovered mechanism employed by infectious bacteria to regulate host cell signaling. However, despite significant effort, only a few host targets have been identified, limiting our understanding of how these pathogens exploit this mechanism to control host cells. Accordingly, we developed a novel nonradioactive AMPylation screening platform using high-density cell-free protein microarrays displaying human proteins produced by human translational machinery.

Manipulation of kinase signaling by bacterial pathogens.

Bacterial pathogens use effector proteins to manipulate their hosts to propagate infection. These effectors divert host cell signaling pathways to the benefit of the pathogen and frequently target kinase signaling cascades. Notable pathways that are usurped include the nuclear factor κB (NF-κB), mitogen-activated protein kinase (MAPK), phosphatidylinositol 3-kinase (PI3K)/Akt, and p21-activated kinase (PAK) pathways.

AMPylation: Something Old is New Again.

The post-translational modification AMPylation is emerging as a significant regulatory mechanism in both prokaryotic and eukaryotic biology. This process involves the covalent addition of an adenosine monophosphate to a protein resulting in a modified protein with altered activity. Proteins capable of catalyzing AMPylation, termed AMPylators, are comparable to kinases in that they both hydrolyze ATP and reversibly transfer a part of this primary metabolite to a hydroxyl side chain of the protein substrate.