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Farnesylated heat shock protein 40 is a component of membrane-bound RISC in Arabidopsis

Sjögren, Lars LU ; Floris, Maïna; Barghetti, Andrea; Völlmy, Franziska; Linding, Rune and Brodersen, Peter (2018) In Journal of Biological Chemistry 293(43). p.16608-16622
Abstract

ARGONAUTE1 (AGO1) binds directly to small regulatory RNA and is a key effector protein of post-transcriptional gene silencing mediated by microRNA (miRNA) and small interfering RNA (siRNA) in Arabidopsis. The formation of an RNA-induced silencing complex (RISC) of AGO1 and small RNA requires the function of the heat shock protein 70/90 chaperone system. Some functions of AGO1 occur in association with endomembranes, in particular the rough endoplasmic reticulum (RER), but proteins interacting with AGO1 in membrane fractions remain unidentified. In this study, we show that the farnesylated heat shock protein 40 homologs, J2 and J3, associate with AGO1 in membrane fractions in a manner that involves protein farnesylation. We also show... (More)

ARGONAUTE1 (AGO1) binds directly to small regulatory RNA and is a key effector protein of post-transcriptional gene silencing mediated by microRNA (miRNA) and small interfering RNA (siRNA) in Arabidopsis. The formation of an RNA-induced silencing complex (RISC) of AGO1 and small RNA requires the function of the heat shock protein 70/90 chaperone system. Some functions of AGO1 occur in association with endomembranes, in particular the rough endoplasmic reticulum (RER), but proteins interacting with AGO1 in membrane fractions remain unidentified. In this study, we show that the farnesylated heat shock protein 40 homologs, J2 and J3, associate with AGO1 in membrane fractions in a manner that involves protein farnesylation. We also show that three changes in AGO1 function are detectable in mutants in protein farnesylation and J2/J3. First, perturbations of the HSP40/70/90 pathway by mutation of J3, HSP90, and farnesyl transferase affect the amounts of AGO1 associated with membranes. Second, miRNA association with membrane-bound polysomes is increased in farnesyl transferase and farnesylation-deficient J2/J3 mutants. Third, silencing by noncell autonomously acting short interfering RNAs is impaired. These observations highlight the involvement of farnesylated J2/J3 in small RNA-mediated gene regulation, and suggest that the importance of chaperone-AGO1 interaction is not limited to the RISC assembly process.

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author
publishing date
type
Contribution to journal
publication status
published
in
Journal of Biological Chemistry
volume
293
issue
43
pages
16608 - 16622
publisher
ASBMB
external identifiers
  • scopus:85055614489
ISSN
0021-9258
DOI
10.1074/jbc.RA118.003887
language
English
LU publication?
no
id
4c90c8f9-7189-4026-b114-eae8fc7b95b0
date added to LUP
2018-12-18 12:52:52
date last changed
2019-02-20 11:40:13
@article{4c90c8f9-7189-4026-b114-eae8fc7b95b0,
  abstract     = {<p>ARGONAUTE1 (AGO1) binds directly to small regulatory RNA and is a key effector protein of post-transcriptional gene silencing mediated by microRNA (miRNA) and small interfering RNA (siRNA) in Arabidopsis. The formation of an RNA-induced silencing complex (RISC) of AGO1 and small RNA requires the function of the heat shock protein 70/90 chaperone system. Some functions of AGO1 occur in association with endomembranes, in particular the rough endoplasmic reticulum (RER), but proteins interacting with AGO1 in membrane fractions remain unidentified. In this study, we show that the farnesylated heat shock protein 40 homologs, J2 and J3, associate with AGO1 in membrane fractions in a manner that involves protein farnesylation. We also show that three changes in AGO1 function are detectable in mutants in protein farnesylation and J2/J3. First, perturbations of the HSP40/70/90 pathway by mutation of J3, HSP90, and farnesyl transferase affect the amounts of AGO1 associated with membranes. Second, miRNA association with membrane-bound polysomes is increased in farnesyl transferase and farnesylation-deficient J2/J3 mutants. Third, silencing by noncell autonomously acting short interfering RNAs is impaired. These observations highlight the involvement of farnesylated J2/J3 in small RNA-mediated gene regulation, and suggest that the importance of chaperone-AGO1 interaction is not limited to the RISC assembly process.</p>},
  author       = {Sjögren, Lars and Floris, Maïna and Barghetti, Andrea and Völlmy, Franziska and Linding, Rune and Brodersen, Peter},
  issn         = {0021-9258},
  language     = {eng},
  number       = {43},
  pages        = {16608--16622},
  publisher    = {ASBMB},
  series       = {Journal of Biological Chemistry},
  title        = {Farnesylated heat shock protein 40 is a component of membrane-bound RISC in Arabidopsis},
  url          = {http://dx.doi.org/10.1074/jbc.RA118.003887},
  volume       = {293},
  year         = {2018},
}