Mammalian class E Vps proteins, SBP1 and mVps2/CHMP2A, interact with and regulate the function of an AAA-ATPase SKD1/Vps4B.

SKD1 belongs to the AAA-ATPase family and is one of the mammalian class E Vps (vacuolar protein sorting) proteins. Previously we have reported that the overexpression of an ATPase activity-deficient form of SKD1 (suppressor of potassium transport growth defect), SKD1(E235Q), leads the perturbation of membrane transport through endosomes and lysosomes, however, the molecular mechanism behind the action of SKD1 is poorly understood. We have identified two SKD1-binding proteins, SBP1 and mVps2, by yeast two-hybrid screening and we assign them as mammalian class E Vps proteins.