<i>β</i>-Cell Receptor Tyrosine Kinases in Controlling Insulin Secretion and Exocytotic Machinery: c-Kit and Insulin Receptor

Oakie, Amanda; Wang, Rennian

doi:10.1210/en.2018-00716

Cited by 14 publications

(9 citation statements)

References 98 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The tyrosine phosphorylation at specific sites of the signaling molecule is precisely regulated by protein tyrosine kinases and protein tyrosine phosphatases (Tonks, 2006; Yu & Zhang, 2018). Although tyrosine kinases such as the insulin receptor, Src, and Fyn are acknowledged to play critical roles in hormone secretion (Jewell et al, 2011; Soares et al, 2013; Meijer et al, 2018; Oakie & Wang, 2018), only a very few PTPs that regulate the vesicle release machinery have been identified, and the structural basis of how these PTPs selectively dephosphorylate the key tyrosine phosphorylation sites governing exocytosis was unknown. In the current study, we demonstrated that PTP‐MEG2 is an important regulator of hormone secretion from the chromaffin cell, using a selective PTP‐MEG2 inhibitor in combination with cellular and electrochemical amperometric recording.…”

Section: Discussionmentioning

confidence: 99%

PTP‐MEG2 regulates quantal size and fusion pore opening through two distinct structural bases and substrates

Chen

Yang

et al. 2021

EMBO Reports

View full text Add to dashboard Cite

Tyrosine phosphorylation of secretion machinery proteins is a crucial regulatory mechanism for exocytosis. However, the participation of protein tyrosine phosphatases (PTPs) in different exocytosis stages has not been defined. Here we demonstrate that PTP-MEG2 controls multiple steps of catecholamine secretion. Biochemical and crystallographic analyses reveal key residues that govern the interaction between PTP-MEG2 and its substrate, a peptide containing the phosphorylated NSF-pY 83 site, specify PTP-MEG2 substrate selectivity, and modulate the fusion of catecholamine-containing vesicles. Unexpectedly, delineation of PTP-MEG2 mutants along with the NSF binding interface reveals that PTP-MEG2 controls the fusion pore opening through NSF independent mechanisms. Utilizing bioinformatics search and biochemical and electrochemical screening approaches, we uncover that PTP-MEG2 regulates the opening and extension of the fusion pore by dephosphorylating the DYNAMIN2-pY 125 and MUNC18-1-pY 145 sites. Further structural and biochemical analyses confirmed the interaction of PTP-MEG2 with MUNC18-1-pY 145 or DYNAMIN2-pY 125 through a distinct structural basis compared with that of the NSF-pY 83 site. Our studies thus provide mechanistic insights in complex exocytosis processes.

show abstract

Section: Discussionmentioning

confidence: 99%

PTP‐MEG2 regulates quantal size and fusion pore opening through two distinct structural bases and substrates

Chen

Yang

et al. 2021

EMBO Reports

View full text Add to dashboard Cite

show abstract

“…In addition, we noticed an augmented expression profile of pathways that contribute to functionality and secretory properties of beta cells as well as other excitable cells. Several key receptors and downstream players representing G‐protein coupled receptor signalling, 43 Tyrosine–kinase receptor signalling 44 and calcium‐dependent signalling 45 as well as those proteins allowing vesicle docking and exocytosis 46–48 were upregulated in 3D‐beta. Consistent with this increase, 3D‐beta were able to respond to glucose by secreting C‐PEP indicating that they possess functional properties.…”

Section: Discussionmentioning

confidence: 99%

PDX1⁻/NKX6.1⁺ progenitors derived from human pluripotent stem cells as a novel source of insulin‐secreting cells

Memon

Younis

Abubaker

et al. 2020

Diabetes Metabolism Res

View full text Add to dashboard Cite

Aim Beta cell replacement strategies are a promising alternative for diabetes treatment. Human pluripotent stem cells (hPSCs) serve as a scalable source for producing insulin‐secreting cells for transplantation therapy. We recently generated novel hPSC‐derived pancreatic progenitors, expressing high levels of the transcription factor NKX6.1, in the absence of PDX1 (PDX1−/NKX6.1+). Herein, our aim was to characterize this novel population and assess its ability to differentiate into insulin‐secreting beta cells in vitro. Materials and Methods Three different hPSC lines were differentiated into PDX1−/NKX6.1+ progenitors, which were further differentiated into insulin‐secreting cells using two different protocols. The progenitors and beta cells were extensively characterized. Transcriptome analysis was performed at different stages and compared with the profiles of various pancreatic counterparts. Results PDX1−/NKX6.1+ progenitors expressed high levels of nestin, a key marker of pancreatic islet‐derived progenitors, in the absence of E‐cadherin, similar to pancreatic mesenchymal stem cells. At progenitor stage, comparison of the two populations showed downregulation of pancreatic epithelial genes and upregulation of neuronal development genes in PDX1−/NKX6.1+ cells in comparison to the PDX1+/NKX6.1+ cells. Interestingly, on further differentiation, PDX1−/NKX6.1+ cells generated mono‐hormonal insulin+ cells and activated pancreatic key genes, such as PDX1. The transcriptome profile of PDX1−/NKX6.1+‐derived beta (3D‐beta) was closely similar to those of human pancreatic islets and purified hPSC‐derived beta cells. Also, the 3D‐beta cells secreted C‐peptide in response to increased glucose concentrations indicating their functionality. Conclusion These findings provide a novel source of insulin‐secreting cells that can be used for beta cell therapy for diabetes.

show abstract

“…The tyrosine phosphorylation at specific sites of the signalling molecule is precisely regulated by protein tyrosine kinases and protein tyrosine phosphatases (Tonks, 2006;Yu and Zhang, 2018). Although tyrosine kinases such as the insulin receptor, Src and Fyn are acknowledged to play critical roles in hormone secretion (Jewell et al, 2011;Meijer et al, 2018;Oakie and Wang, 2018;Soares et al, 2013), only a very few PTPs that regulate the vesicle release machinery have been identified, and the structural basis of how these PTPs selectively dephosphorylate the key tyrosine phosphorylation sites governing exocytosis was unknown. In the current study, we demonstrated that PTP-MEG2 is an important regulator of hormone secretion from the chromaffin cell, using a selective PTP-MEG2 inhibitor in combination with cellular and electrochemical amperometric recording.…”

Section: Discussionmentioning

confidence: 99%

PTP-MEG2 regulates quantal size and fusion pore opening through two distinct structural bases and substrates

Chen

Yang

et al. 2019

Preprint

View full text Add to dashboard Cite

41The tyrosine phosphorylation of secretion machinery proteins is a crucial regulatory 42 mechanism for exocytosis. However, the participation of tyrosine phosphatases in 43 different exocytosis stages has not been defined. Here, we demonstrated that PTP-MEG2 44 controls multiple steps of catecholamine secretion. Biochemical and crystallographic 45 analysis revealed key residues that govern the PTP-MEG2 and NSF-pY 83 site interactions, 46 specify PTP-MEG2 substrate selectivity and modulate the fusion of catecholamine-47 containing vesicles. Unexpectedly, delineation of the PTP-MEG2 mutants along with the 48 NSF interface revealed that PTP-MEG2 controls the fusion pore opening through another 49 unknown substrate. Utilizing a bioinformatics search and biochemical and 50 electrochemical screening, we uncovered that PTP-MEG2 regulates the opening and 51 extension of the fusion pore by dephosphorylating the MUNC18-1 Y 145 site, which is 52 associated with epileptic encephalopathy. The crystal structure of the PTP-53 MEG2/phospho-MUNC18-1-pY 145 segment confirmed the interaction of PTP-MEG2 with 54MUNC18-1 through a distinct structural basis. Our studies extended mechanism insights 55 in complex exocytosis processes. 56 57 KEY WORDS: 58 59 exocytosis, tyrosine phosphorylation, structure, catecholamine, PTP-MEG2 60 61 HIGHLIGHTS: 62 63 PTP-MEG2 regulates multiple steps of exocytosis. 64 A crystal structure of the PTP-MEG2/phosphor-NSF-pY 83 segment was obtained. 65 Functional delineation of the PTP-MEG2/NSF interface resulted in uncovering unknown 66 PTP-MEG2 substrates. 67 PTP-MEG2 regulates fusion pore opening and extension through the MUNC18-1 pY 145 68 site. 69 The distinct structural bases of the recognition of substrates by PTP-MEG2 allows 70 selective inhibitor design. 71 72 73 74 75physiological processes (Wu et al., 2014, Dittman and Ryan, 2019, Neher and Brose, 2018. 79The contents of secreted vesicles include neuronal transmitters, immune factors and other 80 hormones (Alvarez de Toledo et al., 1993, Sudhof, 2013, Magadmi et al., 2019. There are three 81 main exocytosis pathways in secretory cells, namely, full-collapse fusion, kiss-and-run, and 82 compound exocytosis, which possess different secretion rates and lease amount (Sudhof, 2004). 83It was previously reported that the phosphorylation of critical proteins at serine/threonine or 84 tyrosine residues participated in stimulus-secretion coupling in certain important exocytosis 85 processes, for example, the secretion of insulin from pancreatic β cells and of catecholamine 86 from the adrenal medulla (Ortsater et al., 2014, Seino et al., 2009, Laidlaw et al., 2017. 87However, the exact roles of protein tyrosine phosphatases (PTPs) in the regulation of key 88 hormone secretion procedures are not fully understood. 89The 68-kDa PTP-MEG2, encoded by ptpn9, is a non-receptor classical PTP encompassing a 90 unique N-terminal domain with homology to the human CRAL/TRIO domain and yeast Sec14p 91 (Alonso et al., 2004, Gu et al., 1992, Zhang et al., 2012, Zhang e...

show abstract

β-Cell Receptor Tyrosine Kinases in Controlling Insulin Secretion and Exocytotic Machinery: c-Kit and Insulin Receptor

Cited by 14 publications

References 98 publications

PTP‐MEG2 regulates quantal size and fusion pore opening through two distinct structural bases and substrates

PTP‐MEG2 regulates quantal size and fusion pore opening through two distinct structural bases and substrates

PDX1⁻/NKX6.1⁺ progenitors derived from human pluripotent stem cells as a novel source of insulin‐secreting cells

PTP-MEG2 regulates quantal size and fusion pore opening through two distinct structural bases and substrates

Contact Info

Product

Resources

About

β-Cell Receptor Tyrosine Kinases in Controlling Insulin Secretion and Exocytotic Machinery: c-Kit and Insulin Receptor

Cited by 14 publications

References 98 publications

PTP‐MEG2 regulates quantal size and fusion pore opening through two distinct structural bases and substrates

PTP‐MEG2 regulates quantal size and fusion pore opening through two distinct structural bases and substrates

PDX1−/NKX6.1+ progenitors derived from human pluripotent stem cells as a novel source of insulin‐secreting cells

PTP-MEG2 regulates quantal size and fusion pore opening through two distinct structural bases and substrates

Contact Info

Product

Resources

About

PDX1⁻/NKX6.1⁺ progenitors derived from human pluripotent stem cells as a novel source of insulin‐secreting cells