机体细胞镉摄入离子转运通道研究进展

Research Progress in Transport Channels of Cadmium Entry into Cells

镉是人体非必需金属离子,长期镉暴露易引发镉中毒。机体内没有负责镉转运的特定载体,镉可通过必需金属离子转运载体进入机体细胞。机体内能够转运镉的载体有多种,主要包括铁的转运载体二价金属离子转运蛋白1(DMT1)、钙离子通道(电压门控钙通道(VGCC)、瞬时感受器电位(TRP)和钙库调控的钙通道(SOC))以及锌铁调控蛋白ZIP家族中的ZIP8和ZIP14等,且不同的机体细胞镉吸收所需转运载体不同。转运载体对镉离子的转运符合米氏方程,不同载体调节镉吸收的米氏常数Km值不同。机体细胞镉的吸收是个复杂的过程,通常存在着多种转运载体的交互作用,机体细胞可根据环境变化而选择镉的转运载体。对镉的生理毒性,以及细胞镉吸收常用的转运载体类型加以阐述,并分析了不同机体细胞镉吸收的可能转运载体,以期为后续探究机体细胞镉吸收具体分子机制提供理论指导。

Cadmium （Cd） is a nonessential divalent metal ion that can cause toxicity in multiple organs in human body through chronic cadmium exposure. There is no specific transport proteins for cell to absorb Cd, and Cd enter cells by utilizing transport pathways for essential metals. There are many transporters in human cells can transport Cd, including divalent metal transporter 1（DMT1）, calcium channels （voltage-gated calcium channels, VGCC）, transient receptor potential （TRP）, store-operated calcium channels （SOC）, and zinc transporters （ZIP8, ZIP14）. Different tissue cells have different Cd transporters. Transportation of Cd is characterized by michaelis-menten equation, and there are differences among the michaelis constant Km of transporters. Uptake of Cd is a complex interplay of many transporters, and tissue cells can select Cd transporters in accordance with circumtance changes. This paper preferred to discuss Cd toxicity and transporters involved in Cd uptake, and the possible transporters in Cd absorption of different tissue cells were also taken into account, providing theoretical guidance for studying molecular mechanisms of cadmium entry into human cells.