14-3-3ζ suppresses RANKL signaling by destabilizing TRAF6

R. Ayyasamy, S. Fan, P. Czernik, B. Lecka-Czernik, S. Chattopadhyay, R. Chakravarti

Research output: Contribution to journalArticlepeer-review

1 Scopus citations

Abstract

Macrophages are essential regulators of inflammation and bone loss. Receptor activator of nuclear factor-κβ ligand (RANKL), a pro-inflammatory cytokine, is responsible for macrophage differentiation to osteoclasts and bone loss. We recently showed that 14-3-3ζ-knockout (YwhazKO) rats exhibit increased bone loss in the inflammatory arthritis model. 14-3-3ζ is a cytosolic adaptor protein that actively participates in many signaling transductions. However, the role of 14-3-3ζ in RANKL signaling or bone remodeling is unknown. We investigated how 14-3-3ζ affects osteoclast activity by evaluating its role in RANKL signaling. We utilized 14-3-3ζ-deficient primary bone marrow–derived macrophages obtained from wildtype and YwhazKO animals and RAW264.7 cells generated using CRISPR-Cas9. Our results showed that 14-3-3ζ-deficient macrophages, upon RANKL stimulation, have bigger and stronger tartrate-resistant acid phosphatase–positive multinucleated cells and increased bone resorption activity. The presence of 14-3-3ζ suppressed RANKL-induced MAPK and AKT phosphorylation, transcription factors (NFATC1 and p65) nuclear translocation, and subsequently, gene induction (Rank, Acp5, and Ctsk). Mechanistically, 14-3-3ζ interacts with TRAF6, an essential component of the RANKL receptor complex. Upon RANKL stimulation, 14-3-3ζ–TRAF6 interaction was increased, while RANK–TRAF6 interaction was decreased. Importantly, 14-3-3ζ supported TRAF6 ubiquitination and degradation by the proteasomal pathway, thus dampening the downstream RANKL signaling. Together, we show that 14-3-3ζ regulates TRAF6 levels to suppress inflammatory RANKL signaling and osteoclast activity. To the best of our knowledge, this is the first report on 14-3-3ζ regulation of RANKL signaling and osteoclast activation.

Original languageEnglish
Article number107487
JournalJournal of Biological Chemistry
Volume300
Issue number7
DOIs
StatePublished - Jul 2024

Bibliographical note

Publisher Copyright:
© 2024 The Authors

Keywords

  • 14-3-3ζ
  • RANKL
  • TRAF6
  • YWHAZ
  • bone homeostasis
  • macrophages
  • osteoclast
  • protein degradation
  • ubiquitin

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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