14-3-3β isoform is specifically acetylated at Lys51 during differentiation to the osteogenic lineage

Area of Science:

• Biochemistry
• Cell Biology
• Molecular Biology

Background:

• The 14-3-3 protein family regulates numerous signaling pathways through binding to phosphorylated proteins.
• While traditionally viewed as unregulated, 14-3-3 proteins can be inactivated by acetylation at a key lysine residue.
• The specific roles of the seven mammalian 14-3-3 isoforms are increasingly being elucidated.

Purpose of the Study:

• To investigate the acetylation status of 14-3-3 proteins during osteogenic differentiation of human adipose-derived stem cells.
• To determine if 14-3-3 acetylation is linked to specific isoforms and cellular processes like osteogenesis.
• To explore the potential role of the HBO1 acetyltransferase in 14-3-3 acetylation.

Main Methods:

• Studied the acetylation state of lysine 49/51 in 14-3-3 proteins during osteogenic differentiation.
• Utilized overexpression of HBO1 acetyltransferase to assess its effect on 14-3-3 acetylation.
• Performed gene silencing of 14-3-3β and 14-3-3γ isoforms to evaluate their impact on osteogenic potential.

Main Results:

• Acetylation of 14-3-3β at lysine 49/51 (acK49/51) was found to increase during osteogenic differentiation.
• This acetylation was specific to the 14-3-3β isoform, not 14-3-3γ.
• Overexpression of HBO1 enhanced 14-3-3β acK49/51 levels, suggesting HBO1 as a potential catalyst.
• Silencing 14-3-3β, but not 14-3-3γ, significantly enhanced osteogenic differentiation, correlating with increased acetylation.

Conclusions:

• Osteogenic differentiation involves increased acetylation of 14-3-3β at lysine 49/51.
• HBO1 may catalyze this specific posttranslational modification.
• 14-3-3β acetylation appears to negatively regulate osteogenic potential, with implications for bone biology.