Bioorthogonal Engineering of Bacterial Effectors for Spatial–Temporal Modulation of Cell Signaling

Abstract

The complicated and entangled cell signaling network is dynamically regulated by a wide array of enzymes such as kinases. It remains desirable but challenging to specifically modulate individual, endogenous kinases within a cell, particularly in a spatial–temporally controlled fashion. Current strategies toward regulating the intracellular functions of a kinase of interest either lack specificity or require genetic engineering that may perturb its physiological activity. Herein, we harnessed a bacterial effector OspF for optical and chemical modulation of the endogenous mitogen-activated protein kinase (MAPK) cascade in living cells and mice. The phospho-lyase OspF provided high specificity and spatial resolution toward the desired kinase such as the extracellular signal-regulated kinase (ERK), while the genetically encoded bioorthogonal decaging strategy enabled its temporal activation in living systems. The photocaged OspF (OspF*) was applied to dissect the subcellular signaling roles of ERK in nucleus as opposed to cytoplasm, while the chemically caged OspF (OspFc) was introduced into living mice to modulate ERK-mediated gene expression. Finally, our spatially and chemically controlled OspFc was further used to precisely tune immune responses in T cells. Together, our bioorthogonal engineering strategy on bacterial effectors offers a general tool to modulate cell signaling with high specificity and spatial–temporal resolution.

Synthetic methodology towards allylictrans-cyclooctene-ethers enables modification of carbohydrates: bioorthogonal manipulation of thelacrepressor

“…Subsequently, we analyzed whether deprotection with the prokaryote-compatible 3,6-dimethyl-tetrazine (26) could be used to switch on recombinant protein expression. 12,42 We found that 26 caused a minor delay on IPG (15) induced OVA expression without reducing overall expression levels ( Fig. S5 and Table S10 †).…”

“…1A). 7,8 The excellent biocompatibility and high bimolecular reaction rate of the IEDDA pyridazine elimination 9 has given rise to a multitude of in vitro and in vivo applications such as the regulation of protein activity [10][11][12] and the activation of pro-drugs, in which spatiotemporal control is achieved by antibody-drug conjugates (ADCs), [13][14][15] nanoparticles, 16 enzymatic supramolecular self-assembly 17 or hydrogel injection. 18,19 To date, nearly all applications for this reaction have relied on the protection of (primary) amines as TCO-carbamates ( Fig.…”

Dehydroamino acid chemical biology: an example of functional group interconversion on proteins

“…Since the constitutively active OspF irreversibly inhibits MAPK activity, geneticallyencoded decaging strategies were recently developed to provide controlled activation of the phospholyase in different contexts, including in vivo applications. 23,24 For instance, a chemicallycaged OspF (termed OspF c ) was engineered to contain a transcyclooctene (TCO) lysine at the catalytic residue K134 which ablated activity, and an inverse electron demand Diels-Alder reaction with 3,6-dimethyl-1,2,4,5-tetrazine (Me 2 -Tz) 25,26 released the active parent Fig. 2 A chemical de-caging strategy enabling control of the phospholyase activity of the bacterial enzyme OspF that irreversibly inactivates ERK1 via dehydrobutyrine (Dhb) formation.…”

“…2 A chemical de-caging strategy enabling control of the phospholyase activity of the bacterial enzyme OspF that irreversibly inactivates ERK1 via dehydrobutyrine (Dhb) formation. 23 A key step in the process is the use of the inverse electron demand Diels-Alder reaction to remove the TCO from the modified OspF to reveal the catalytic lysine that triggers phosphate elimination on p-ERK1 (OspF structure: PDB 3I0U; ERK1 structure: PDB 2ZOQ; TCO = trans-cyclooctene; Me 2 -Tz = 3,6-dimethyl-1,2,4,5-tetrazine). enzyme (Fig.…”

“…Further applications of phospholyases in human cells and the development of enzyme delivery vehicles such as lipid nanoparticles, hold considerable promise in synthetic biology with potential in vivo applications. 23,24,53 These enzymes could also be used to advance novel bioconjugation approaches and generate chemically homogeneous biotherapeutics that facilitate rational design and elucidation of structure-function relationships.…”