14-3-3 proteins sequester a pool of soluble TRIM32 ubiquitin ligase to repress autoubiquitylation and cytoplasmic body formation

Tohru Ichimura, Masato Taoka, Ikuo Shoji, Hiroki Kato, Tomonobu Sato, Shigetsugu Hatakeyama, Toshiaki Isobe, Naomi Hachiya

Research output: Contribution to journalArticlepeer-review

23 Citations (Scopus)

Abstract

Deregulated expression of tripartite motif-containing protein 32 (TRIM32, an E3 ubiquitin-protein ligase) contributes to various diseases. Here we report, using quantitative proteomics and biochemistry, that 14-3-3 proteins bind to phosphorylated TRIM32 and prevent TRIM32 autoubiquitylation and the formation of TRIM32-containing cytoplasmic bodies, which are potential autoregulatory mechanisms that can reduce the concentration of soluble free TRIM32. The 14-3-3-TRIM32 interaction is dependent on protein-kinase-A-catalyzed phosphorylation of TRIM32 at Ser651. We found that the inhibitory effect of 14-3-3 is, in part, a consequence of disrupting the propensity of TRIM32 to undergo higher-order self-association without affecting its dimerization. Consequently, dimerized TRIM32 bound to 14-3-3 was sequestered in a distinct cytoplasmic pool away from the microtubule network, whereas a TRIM32 mutant that cannot bind 14-3-3 underwent multimerization and was unavailable to facilitate cell growth. Our results reveal a novel connection between ubiquitylation and phosphorylation pathways, which could modulate a variety of cell events by stimulating the formation of the 14-3-3-TRIM32 signaling complex.

Original languageEnglish
Pages (from-to)2014-2026
Number of pages13
JournalJournal of cell science
Volume126
Issue number9
DOIs
Publication statusPublished - May 2013

All Science Journal Classification (ASJC) codes

  • Cell Biology

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