Open AccessChaperone Hsp27, a Novel Subunit of AUF1 Protein Complexes, Functions in AU-Rich Element-Mediated mRNA Decay
Author(s) -
Kristina S. Sinsimer,
Frances M. Gratacós,
Anna M. Knapinska,
Jiebo Lu,
Christopher D. Krause,
Alexandria V. Wierzbowski,
Lauren R. Maher,
S. Scrudato,
Yonaira M. Rivera,
Swati Gupta,
Danielle K. Turrin,
Mary Pauline De La Cruz,
Sidney Pestka,
Gary Brewer
Publication year - 2008
Publication title -
molecular and cellular biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.14
H-Index - 327
eISSN - 1067-8824
pISSN - 0270-7306
DOI - 10.1128/mcb.00431-08
Subject(s) - biology , microbiology and biotechnology , proinflammatory cytokine , protein subunit , messenger rna , inflammation , biochemistry , immunology , gene
Controlled, transient cytokine production by monocytes depends heavily upon rapid mRNA degradation, conferred by 3′ untranslated region-localized AU-rich elements (AREs) that associate with RNA-binding proteins. The ARE-binding protein AUF1 forms a complex with cap-dependent translation initiation factors and heat shock proteins to attract the mRNA degradation machinery. We refer to this protein assembly as the AUF1- and signal transduction-regulated complex, ASTRC. Rapid degradation of ARE-bearing mRNAs (ARE-mRNAs) requires ubiquitination of AUF1 and its destruction by proteasomes. Activation of monocytes by adhesion to capillary endothelium at sites of tissue damage and subsequent proinflammatory cytokine induction are prominent features of inflammation, and ARE-mRNA stabilization plays a critical role in the induction process. Here, we demonstrate activation-induced subunit rearrangements within ASTRC and identify chaperone Hsp27 as a novel subunit that is itself an ARE-binding protein essential for rapid ARE-mRNA degradation. As Hsp27 has well-characterized roles in protein ubiquitination as well as in adhesion-induced cytoskeletal remodeling and cell motility, its association with ASTRC may provide a sensing mechanism to couple proinflammatory cytokine induction with monocyte adhesion and motility.