Table 1. Function and intracellular localization of ABCC6 variants.

ABCC6 variant	Stability in Sf9	MgATP binding	ATPase catalytic intermediate	Transport activity(% of WT)	Plasmamembrane localization in mouse liver*	Intracellular localization in mouse liver*
WT	Stable	yes	yes	100%	+++++	−
ΔABCC6	Stable	n.d.	n.d.	<10%	−	+++++
R1138Q	Stable	yes	yes	∼85%	++	+++
V1298F	Stable	yes	no	<10%	+++++	−
G1321S	Stable	yes	no	<10%	−	+++++
R1314W	Stable	yes	yes	∼90%	+	++++(ER)
R1339C	Unstable	n.a.	n.a.	n.a.	−	+++++

n.d.: not determined.

n.a.: not applicable.

(ER): mostly retained with the endoplasmic reticulum.

*Plasma membrane and intracellular localization was determined independently by five of the co-authors using (+++++) for the plasma membrane and (−) for the intracellular localization of the WT and (−) for the plasma membrane and+++++for the intracellular localization of ΔABCC6, respectively.