Dependence of Ypt1 and Sec4 membrane attachment on Bet2.
Many small GTP-binding proteins are synthesized as soluble proteins that are post-translationally modified as a prerequisite for membrane attachment. Ypt1 and Sec4 are homologous Raslike GTP-binding proteins that have been proposed to regulate the specificity of vesicular traffic at different stages of the secretory pathway by cycling on and off membranes. Here we show that BET2, initially identified as a gene required for transport from endoplasmic reticulum to Golgi apparatus in yeast, encodes a factor that is needed for the membrane attachment of Ypt1 and Sec4. DNA sequence analysis has revealed that Bet2 is homologous to Dpr1 (Ram1), an essential component of a protein prenyltransferase that modifies Ras, enabling it to attach to membranes. We propose that Bet2 modifies Ypt1 and Sec4 in an analogous manner.
Rossi
G
G
Department of Cell Biology, Yale University School of Medicine, New Haven, Connecticut 06510.
Yu
J A
JA
Newman
A P
AP
Ferro-Novick
S
S
D000595:Amino Acid Sequence; D002462:Cell Membrane / Q000378:metabolism; D003001:Cloning, Molecular; D003433:Crosses, Genetic; D005656:Fungal Proteins / Q000235:genetics* / Q000378:metabolism*; D019204:GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D005800:Genes, Fungal; D005816:Genetic Complementation Test; D006056:Golgi Apparatus / Q000378:metabolism; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D009154:Mutation; D011506:Proteins / Q000235:genetics / Q000378:metabolism*; D012441:Saccharomyces cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D020691:rab GTP-Binding Proteins
D005656:Fungal Proteins; D008565:Membrane Proteins; D011506:Proteins; D029701:Saccharomyces cerevisiae Proteins; D019204:GTP-Binding Proteins; C060755:YPT1 protein, S cerevisiae; C064320:SEC4 protein, S cerevisiae; D020691:rab GTP-Binding Proteins