Phospholipid scramblase involved in endosome biogenesis; functions with Vps13p, a lipid transfer protein, the biogenesis of multivesicular bodies (MVBs); functions antagonistically to flippases, with the null suppressing growth and membrane trafficking defects of flippase null alleles; PQ loop family member; cycles between early endosomes and the trans-Golgi network; non-essential gene; orthogous to human SLC66A2