Determinants of Rbp1p Localization in Specific Cytoplasmic Mrna- Processing Foci, P-Bodies
Resource
JOURNAL OF BIOLOGICAL CHEMISTRY v.281 n.39 pp.29379-29390
Journal
JOURNAL OF BIOLOGICAL CHEMISTRY
Journal Volume
v.281
Journal Issue
n.39
Pages
29379-29390
Date Issued
2006
Date
2006
Author(s)
BUU, LEH-MIAUH
LEE, FANG-JEN S
Abstract
Rbp1p, a yeast RNA-binding protein, decreases the level of mitochondrial porin mRNA by enhancing its degradation, but the intracellular location of the Rbp1p-mediated degradation complex remains unknown. We show here that Rbp1p in xrn1 Delta mutant yeast localizes in specific cytoplasmic foci that are known as P-bodies. The N-terminal and RNA recognition motif (RRM) 1 domains of Rbp1p are necessary but not sufficient for its localization in P bodies. Rbp1p forms oligomers through its C-terminal domain in vivo; N- terminal-delete, or RRM1-mutated Rbp1p can be more efficiently recruited to P-bodies in an xrn1 Delta strain, expressing a full-length Rbp1p. Although POR1 mRNA is localized to P bodies in an xrn1 Delta strain , this localization does not depend on Rbp1p. Decapping activator Dhh1p directly interacts with Rbp1p. However, the recruitment of Rbp1p to P- bodies does not require Dhh1p or Ccr4p. In wildtype cells, Rbp1p can localize to P-bodies under glucose deprivation or treatment with KCl. In addition , Rbp1p-mediated porin mRNA decay is elicited by Xrn1p, a 5' to 3 ' exonuclease. These results provide new insight into the mechanism of Rbp 1p function.