TLC

TRPML1 Lysosomal Calcium Sensor

A genetically encoded calcium sensor for monitoring TRPML1 activity and lysosomal Ca²⁺ release

Transient receptor potential mucolipin-1 (TRPML1) is a lysosomal ion channel that regulates Ca²⁺ release from the lysosome. TRPML1-mediated Ca²⁺ signaling has been implicated in lysosomal function, autophagy, membrane trafficking, cellular metabolism, and disease.
Our TRPML1 calcium sensor provides a genetically encoded approach to monitor Ca²⁺ dynamics associated with TRPML1 activity in live cells. Our sensor is designed to provide a direct fluorescent readout of TRPML1-associated Ca²⁺ signaling, enabling researchers to monitor changes dynamically in living cells.
The TLC sensor is bright enough to be used on standard plate readers in drug discovery because TRPML1 is an emerging drug target for neurodegenerative diseases, breast and lung cancer, and potentially viral infections.

• Genetically encoded — expresses in cell line of choice, primary neurons, iPSC-derived cell types, and immortalized cell lines; no exogenous dye loading or washout steps.
• BacMam delivery — fast, efficient, dose-controlled transduction across a broad range of mammalian cell types, including cells that are difficult to transfect.
• Live-cell, real-time — track dynamics from seconds or hours to days, not a single fixed snapshot.
• TRPML1–targeted — The GECO biosensor is a green Ca²⁺ sensor fused to the cytoplasmic side of the TRPML1 channel, distinct from cytosolic or ER Ca²⁺ pools.
• Screen in 384 well format or resolve single cell lysosomes — Same virus, same cells, no reoptimization. Plate reader and microscope compatible.
  

Application of known TRPML1 agonists results in persistent and robust activation, confirming TRPML1 functionality. Tested the TLC sensor in HEK293T cells and stimulated with known agonists of TRPML1.

TRPML1 inhibitor (ML-SI3) blocks the TRPML1 agonist (MK6-83) stimulated Ca²⁺ response but does not abolish the calcium response from carbachol. The addition of the inhibitor completely blocked the MK6-83 triggered Ca²⁺ release, but not the ER Ca²⁺ release triggered by activation of the muscarinic receptor.