Multi-site Neurogenin3 Phosphorylation Controls Pancreatic Endocrine Differentiation
Roberta Azzarelli1, Christopher Hurley2, Magdalena K Sznurkowska1
1Department of Oncology, University of Cambridge, Hutchison/MRC Research Centre, Hills Road, Cambridge CB2 0XZ, UK; Wellcome Trust-Medical Research Council Cambridge Stem Cell Institute, University of Cambridge, Tennis Court Road, Cambridge CB2 1QR, UK.
Developmental Cell
|May 2, 2017
Summary
Phosphorylation of Neurogenin3 (Ngn3) protein by cyclin-dependent kinases (Cdks) is crucial for pancreatic endocrine cell development. Modulating Ngn3 phosphorylation enhances cell differentiation and maintains beta cell function.
Area of Science:
- Cellular and Molecular Biology
- Developmental Biology
- Endocrinology
Background:
- The proneural transcription factor Neurogenin3 (Ngn3) is essential for pancreatic endocrine cell differentiation.
- Regulation of Ngn3 protein activity, particularly post-translational modifications like phosphorylation, remains largely uncharacterized.
Purpose of the Study:
- To investigate the role of Ngn3 protein phosphorylation in pancreatic endocrine development and beta cell function.
- To explore the impact of modulating Ngn3 phosphorylation on alpha cell generation and ductal reprogramming.
Main Methods:
- Utilized phosphomutant forms of Ngn3 to assess the functional consequences of phosphorylation.
- Analyzed Ngn3 protein stability, DNA binding affinity, and target gene expression.
- Investigated Ngn3's role in adult beta cells under conditions of elevated c-Myc and during ductal reprogramming.
Main Results:
- Demonstrated that Ngn3 protein undergoes cyclin-dependent kinase (Cdk)-mediated phosphorylation on multiple serine-proline sites.
- Phosphorylation-deficient Ngn3 mutants enhanced alpha cell generation and promoted endocrine specification during ductal reprogramming.
- Unphosphorylated Ngn3 maintained insulin expression in adult beta cells with elevated c-Myc, and preventing multi-site phosphorylation increased Ngn3 stability and DNA binding.
Conclusions:
- Multi-site phosphorylation of Ngn3 acts as a critical regulatory mechanism controlling its function in pancreatic endocrine differentiation.
- Modulating Ngn3 phosphorylation can enhance its ability to promote endocrine differentiation and maintain beta cell function.
- These findings suggest potential therapeutic strategies for manipulating Ngn3 activity to promote endocrine cell development in vitro and in vivo.
