IDENTIFICATION OF A NOVEL MAMMALIAN MEMBER OF THE NSF/CDC48P/PAS1P/TBP-1 FAMILY THROUGH HETEROLOGOUS EXPRESSION IN YEAST

Abstract Two suppressors of the growth deficiency of a potassium transport mutant of Saccharomyces cerevisiae were isolated from a mouse cDNA expression library. These suppressors, SKD1 and SKD2 ( s uppressor of K + transport growth d efect), were cDNAs encoding members of a family of ATPases involved in membrane fusion ( N -ethylmaleimide-sensitive fusion protein, NSF), cell division cycle regulation (CDC48p), peroxisome assembly (Pas1p), and transcriptional regulation (TBP-1). The SKD1 protein constitutes a novel member of this family with 49–58% amino acid sequence similarity with other family members, and contains a single ATP binding site. The SKD2 polypeptide is the mouse homolog of NSF.