Inducible expression and phosphorylation of coactivator BOB.1/OBF.1 in T cells

Area of Science:

• Molecular Biology
• Immunology
• Gene Regulation

Background:

• BOB.1/OBF.1 is a transcriptional coactivator constitutively expressed in B cells.
• It interacts with Oct1 and Oct2 transcription factors, key regulators in B cell development and function.

Purpose of the Study:

• To investigate the regulation of BOB.1/OBF.1 activity.
• To determine the role of posttranslational modifications, specifically phosphorylation, in BOB.1/OBF.1 function.
• To elucidate the cell type-specific mechanisms of BOB.1/OBF.1-mediated gene expression.

Main Methods:

• Analysis of BOB.1/OBF.1 expression and transactivation function in activated Jurkat T cells and murine thymocytes.
• In vivo and in vitro phosphorylation studies of BOB.1/OBF.1 at Ser184.
• Site-directed mutagenesis of Ser184 to assess its impact on transactivation in both T and B cells.

Main Results:

• BOB.1/OBF.1 expression and transactivation function were induced upon activation of T cells.
• Phosphorylation at Ser184 was identified as a critical modification for inducible T cell activation.
• Mutation of Ser184 impaired transactivation in B cells, indicating constitutive phosphorylation in these cells.

Conclusions:

• BOB.1/OBF.1 is a key transcriptional coactivator regulated by phosphorylation.
• Posttranslational modification at Ser184 is essential for both inducible T cell activation and constitutive B cell function.
• These findings highlight the role of phosphorylation in mediating cell type-specific gene expression by BOB.1/OBF.1.