A Covalent Targeted Platform for Protein Dynamic Tracking

Long-term imaging of the protein dynamics within living cells is crucial for understanding the mechanism of disease occurrence and developing efficient diagnosis and treatment. However, the current probes suffer from a short intracellular retention and rapid clearance. Herein, we develop a covalent targeted imaging platform (CTI) for protein dynamic tracking in living cells. The peptide-conjugated probe can achieve covalent recognition of the target protein with a peptide ligand. In tandem, the maleimide group reacts with a cysteine sulfhydryl group on the target protein to form a covalent bond. This bond formation concomitantly restricts the rotation of a fluorescent molecular rotor, resulting in the activation of a long-term fluorescent signal. As a proof of concept, the probe (MXQ) successfully enabled long-term stable tracking and precise treatment monitoring of the X-linked inhibitor of apoptosis protein (XIAP) within living MCF-7 cells. We have, for the first time, reported a covalent targeted and generalizable platform for potentially accelerating its biomedical application for diverse diseases.