Ubiquitin-like protein MNSFβ noncovalently binds to molecular chaperone HSPA8 and regulates osteoclastogenesis

Area of Science:

• Molecular Biology
• Cell Biology
• Biochemistry

Background:

• Monocyte neutrophil तेव्हा-like factor beta (MNSFβ) is a ubiquitin-like protein known to covalently bind target proteins.
• Identifying novel MNSFβ-interacting proteins and their functions is crucial for understanding cellular processes.

Purpose of the Study:

• To identify novel protein substrates of MNSFβ.
• To investigate the functional significance of the MNSFβ-HSPA8 interaction in osteoclastogenesis.

Main Methods:

• MALDI-TOF MS fingerprinting was used to identify MNSFβ-interacting proteins.
• In vitro binding assays were performed to assess MNSFβ-HSPA8 interaction in the presence of ATP.
• Double knockdown experiments of MNSFβ and HSPA8 were conducted in Raw264.7 cells.

Main Results:

• Heat shock 70-kDa protein 8 (HSPA8) was identified as a novel MNSFβ-interacting protein.
• MNSFβ noncovalently binds to HSPA8 in vitro.
• Double knockdown of MNSFβ and HSPA8 significantly inhibited RANKL-induced osteoclastogenesis, ERK1/2 and p38 phosphorylation, and TNFα production.

Conclusions:

• MNSFβ interacts noncovalently with HSPA8, a novel finding for MNSFβ-protein substrate binding.
• The MNSFβ-HSPA8 association plays a role in promoting RANKL-induced osteoclastogenesis and associated inflammatory signaling.