A previously uncharacterized yeast protein, YJL066c, was discovered in the
membrane fraction although it has no hydrophobic stretch. The protein was p
artly solubilized by Triton X-100 in an oligomeric form, while it was insol
uble in alkali or salt. By immunofluorescent microscopy, its localization c
oincided with the mitochondria. We therefore propose it should be named Mpm
1 (mitochondrial peculiar membrane protein 1).