Cell-Impermeable Inhibitors Confirm That Intracellular Human Transglutaminase 2 Is Responsible for the...

Area of Science:

• Biochemistry
• Enzymology
• Molecular Biology

Background:

• Transglutaminase 2 (TG2) is a key enzyme in protein crosslinking and G-protein signaling, implicated in diseases like cancer and fibrosis.
• Current TG2 therapies lack subcellular selectivity, hindering targeted treatment approaches.
• No existing tools can differentiate between extracellular and intracellular TG2 activity.

Purpose of the Study:

• To design novel TG2 inhibitors and probes with improved subcellular selectivity.
• To develop cell-impermeable inhibitors targeting extracellular TG2.
• To create fluorescent and alkyne-handle probes for labeling both intra- and extracellular TG2.

Main Methods:

• Design and synthesis of novel TG2-selective inhibitors and probes.
• Development of cell-impermeable irreversible inhibitors.
• Creation of intrinsically fluorescent and alkyne-functionalized TG2 probes.
• Cellular imaging and pull-down assays using developed probes.

Main Results:

• Novel TG2 inhibitors were developed that are potent, irreversible, and cell-impermeable, selectively targeting extracellular TG2.
• Fluorescent TG2 probes were successfully internalized and imaged in cells.
• Experimental evidence suggests intracellular TG2, likely via its G-protein activity, contributes to cancer progression.

Conclusions:

• Novel chemical tools enable selective targeting and investigation of TG2's subcellular functions.
• Distinguishing between extracellular and intracellular TG2 activity is crucial for understanding its role in disease.
• These findings pave the way for developing targeted therapies for TG2-associated pathologies.