Biogenesis of the signal recognition particle (SRP) involves import of SRP proteins into the nucleolus, assembly with the SRP-RNA, and Xpo1p-mediated export.

ABSTRACT: The signal recognition particle (SRP) targets nascent secretory proteins to the ER, but how and where the SRP assembles is largely unknown. Here we analyze the biogenesis of yeast SRP, which consists of an RNA molecule (scR1) and six proteins, by localizing all its components. Although scR1 is cytoplasmic in wild-type cells, nuclear localization was observed in cells lacking any one of the four SRP "core proteins" Srp14p, Srp21p, Srp68p, or Srp72p. Consistently, a major nucleolar pool was detected for these proteins. Sec65p, on the other hand, was found in both the nucleoplasm and the nucleolus, whereas Srp54p was predominantly cytoplasmic. Import of the core proteins into the nucleolus requires the ribosomal protein import receptors Pse1p and Kap123p/Yrb4p, which might, thus, constitute a

SUBMITTER: Grosshans H 

PROVIDER: S-EPMC2192394 | biostudies-literature | 2001 May

REPOSITORIES: biostudies-literature