Bipartite signals mediate subcellular targeting of tail-anchored membrane proteins in Saccharomyces cerevisiae.
Tail-anchored proteins have an NH(2)-terminal cytosolic domain anchored to intracellular membranes by a single, COOH-terminal, transmembrane segment. Sequence analysis identified 55 tail-anchored proteins in Saccharomyces cerevisiae, with several novel proteins, including Prm3, which we find is required for karyogamy and is tail-anchored in the nuclear envelope. A total of six tail-anchored proteins are present in the mitochondrial outer membrane and have relatively hydrophilic transmembrane segments that serve as targeting signals. The rest, by far the majority, localize via a bipartite system of signals: uniformly hydrophobic tail anchors are first inserted into the endoplasmic reticulum, and additional segments within the cytosolic domain of each protein can dictate subsequent sorting to a precise destination within the cell.
Beilharz
Traude
T
Russell Grimwade School of Biochemistry & Molecular Biology, University of Melbourne, Parkville 3010, Australia.
Egan
Billie
B
Silver
Pamela A
PA
Hofmann
Kay
K
Lithgow
Trevor
T
D000595:Amino Acid Sequence; D004721:Endoplasmic Reticulum / Q000378:metabolism; D008565:Membrane Proteins / Q000378:metabolism*; D008856:Microscopy, Fluorescence; D008969:Molecular Sequence Data; D016296:Mutagenesis; D012441:Saccharomyces cerevisiae / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction; D013347:Subcellular Fractions / Q000378:metabolism*
D008565:Membrane Proteins; D029701:Saccharomyces cerevisiae Proteins