Investigation of the role of TRPML channel family and two-pore channel family members in intracellular fusion processes and the cation homeostasis of endolysosomal vesicles

阳离子稳态和pH调节对内体、溶酶体和溶酶体相关细胞器（LROs）如黑素小体的功能至关重要。虽然人们已经知道溶酶体和LROs的酸化是如何实现的，即主要是通过atp驱动的质子泵（液泡H+- atp酶），但对于内体、溶酶体、黑素体或其他LROs的腔内pH的精细调节，以及腔内阳离子浓度（如钙、钠和钾）的调节，以及重金属（如铁、锌、铜）的调节，仍然知之甚少。进一步不清楚的是不同的内溶酶体融合过程是如何被调节的，以及大多数这种融合过程所必需的钙是如何提供的。非选择性阳离子通道的TRP（瞬时受体电位）家族成员，特别是粘磷脂TRPML1-3以及双孔通道（TPCs）， TPC1和TPC2，优先在内溶酶体系统中表达，并可能在上述过程的调节中发挥决定性作用。通过分析敲除小鼠模型以及蛋白-蛋白相互作用，探讨TRPML通道和TPCs在这一过程中的生理作用和功能。

Cation homeostasis and pH regulation are essential for the function of endosomes, lysosomes and lysosome-related organelles (LROs) such as melanosomes. Although it has been known for a while how acidification of lysosomes and LROs is achieved, i.e. primarily via ATP-driven proton pumps (vacuolar H+-ATPases), still relatively little is known about the fine regulation of luminal pH in endosomes, lysosomes, melanosomes, or other LROs as well as the regulation of intraluminal cation concentrations such as calcium, sodium and potassium, but also heavy metals such as iron, zinc, copper for example. Further unclear is how the different endolysosomal fusion processes are regulated and how the calcium that appears to be necessary for most of such fusion processes is provided. Members of the TRP (transient receptor potential) family of non-selective cation channels, in particular the mucolipins TRPML1-3 as well as the two-pore channels (TPCs), TPC1 and TPC2, are preferentially expressed in the endolysosomal system and are likely to play decisive roles in the regulation of the above mentioned processes. By analyzing knock-out mouse models as well as protein-protein interactions the physiological role and function of TRPML channels and TPCs in such processes shall be investigated.