Table 1.

Dysregulation of different types of metal ion transporters in the AD brain.

Biometal	Transporters	Expression	Biological functions	Reference
Iron	DMT1	↑	Transport Fe2+, Cu2+, Mn2+ into cytosol	Zheng et al., 2009
	Tf/TfR	↑	Tf/TfR is endocytosed, by which Fe3+ is reduced to Fe2+	Moos and Morgan, 2000
	Lf/LfR	↑	Lf/LfR complex facilitate Fe3+ uptake	An et al., 2009
	Fpn	↓	Mediate Fe2+, Mn2+ export out of cells	Xian-hui et al., 2015
	MTf		Transport Fe3+ across the BBB	Kim et al., 2001
Copper	CTR1		Cell surface Cu+ uptake	Lang et al., 2013
	ATP7A	↑	Cellular Cu+ exporter	Zheng et al., 2010
	ATP7B	↑	Cellular Cu+ exporter
Zinc	ZnT3	↓	Export Zn2+ from neurons	Adlard et al., 2010
	ZIPs		Zn2+ uptake	Greenough et al., 2011
	MT1, MT2	↑	Expressed in astrocytes for Zn2+ uptake	Hidalgo et al., 2006
	MT3	↓	Expressed in neurons for Zn2+ uptake
Manganese	ZIP8,ZIP14		Mn2+ influx into the cytosol	Bekerydemir et al., 2017; Lin et al., 2017
	DAT		Mn2+ influx into the cytosol	Chen et al., 2006
	ATP13A2	↓	Transport Mn2+ into the lysosomes	Murphy et al., 2013
	SLC30A10	↓	Mediate efflux of Mn2+	Tuschl et al., 2016
	SPCA1		Transport Mn2+ into the Golgi	Ton et al., 2002
Magnesium	MagT1		Mediate Mg2+ influx	Goytain and Quamme, 2005
	TRPM6/TRPM7	↑	Mg2+ entry channel	Sun et al., 2015
	SLC41A1		Mediate Na+-dependent Mg2+ extrusion	Kolisek et al., 2012
Calcium	VGCC		Control Ca2+ influx under electrical activity	Thibault et al., 2007
	Na+/Ca2+ exchanger		Extrude Ca2+ from the cytoplasm in exchange for Na+ entry	Wu M.P. et al., 2008
	NMDAR	↑	Mediate Ca2+ influx	Birnbaum et al., 2015
	AMPAR	↑	Mediate Ca2+ influx	Whitehead et al., 2017
	P2X7R	↑	Mediate Ca2+ influx	Lee et al., 2011