The lysosomal Ca2+ release channel TRPML1 regulates lysosome size by activating calmodulin

作者：Qi Cao, Yi Yang, Xi Zoë Zhong, Xian‐Ping Dong · 发表于：Journal of Biological Chemistry · 年份：2017 · DOI：10.1074/jbc.m116.772160 · 被引用次数：127 · 研究领域：Calcium signaling and nucleotide metabolism、Plant Molecular Biology Research

Intracellular lysosomal membrane trafficking, including fusion and fission, is crucial for cellular homeostasis and normal cell function. Both fusion and fission of lysosomal membrane are accompanied by lysosomal Ca 2+ release. We recently have demonstrated that the lysosomal Ca 2+ release channel P2X4 regulates lysosome fusion through a calmodulin (CaM)-dependent mechanism. However, the molecular mechanism underlying lysosome fission remains uncertain. In this study, we report that enlarged lysosomes/vacuoles induced by either vacuolin-1 or P2X4 activation are suppressed by up-regulating the lysosomal Ca 2+ release channel transient receptor potential mucolipin 1 (TRPML1) but not the lysosomal Na + release channel two-pore channel 2 (TPC2). Activation of TRPML1 facilitated the recovery of enlarged lysosomes/vacuoles. Moreover, the effects of TRPML1 on lysosome/vacuole size regulation were eliminated by Ca 2+ chelation, suggesting a requirement for TRPML1-mediated Ca 2+ release. We further demonstrate that the prototypical Ca 2+ sensor CaM is required for the regulation of lysosome/vacuole size by TRPML1, suggesting that TRPML1 may promote lysosome fission by activating CaM. Given that lysosome fission is implicated in both lysosome biogenesis and reformation, our findings suggest that TRPML1 may function as a key lysosomal Ca 2+ channel controlling both lysosome biogenesis and reformation.