Human Pannexin 1 Channel is Not Phosphorylated by Src Tyrosine Kinase at Tyr199 and Tyr309

Khái niệm cốt lõi

Pannexin 1 (PANX1) channel is not phosphorylated by Src tyrosine kinase at Tyr199 and Tyr309 residues, contrary to previous reports.

Tóm tắt

The content examines the regulation of the large-pore channel Pannexin 1 (PANX1) by tyrosine phosphorylation. Previous studies had reported that the non-receptor tyrosine kinase Src phosphorylates PANX1 at Tyr198 and Tyr308 (equivalent to Tyr199 and Tyr309 in human PANX1), leading to channel activation. However, the authors provide evidence that the commercially available antibodies used to detect these phosphorylation sites are non-specific and do not reliably recognize phosphorylated PANX1.
The authors first mapped the locations of Tyr199 and Tyr309 in the PANX1 structure, showing they are partially or fully buried, making them less accessible for phosphorylation. They then used multiple techniques, including Phos-tag gel analysis, mass spectrometry, and electrophysiology, to investigate PANX1 phosphorylation by Src in heterologous expression systems. The results consistently demonstrate that human and mouse PANX1 are not phosphorylated by Src at these two tyrosine residues, contrary to the previous reports.
The authors call for the research community to re-examine the existing paradigm of tyrosine phosphorylation-dependent activation of the PANX1 channel, as the commercially available phospho-specific antibodies used in prior studies appear to be non-specific. They emphasize the importance of using complementary techniques, such as mass spectrometry, to independently verify novel phosphorylation sites, rather than solely relying on western blot analysis with potentially unreliable antibodies.

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Human Pannexin 1 Channel is NOT Phosphorylated by Src Tyrosine Kinase at Tyr199 and Tyr309

by Ruan,Z., Du,... lúc www.biorxiv.org 09-12-2023

https://www.biorxiv.org/content/10.1101/2023.09.10.557063v3

Yêu cầu sâu hơn

What other post-translational modifications, besides tyrosine phosphorylation, might regulate the activity and function of the PANX1 channel?

Post-translational modifications play a crucial role in regulating protein activity and function, including that of the PANX1 channel. Besides tyrosine phosphorylation, other modifications that might regulate PANX1 include:

Serine Phosphorylation: Serine phosphorylation has been reported to impact PANX1 channel activity. For example, Ser205 and Ser206 phosphorylation in murine PANX1 has shown contradictory effects on channel activity, indicating the potential role of serine phosphorylation in PANX1 regulation.

Glycosylation: Glycosylation at specific sites on PANX1 has been shown to affect channel function. For instance, glycosylation at the second extracellular loop of PANX1 sterically prevents the docking of PANX1 heptamers, influencing channel assembly and activity.

Protease Cleavage: Protease cleavage of the regulatory C-terminal tail of PANX1 has been implicated in apoptotic cell clearance, suggesting a role for protease-mediated post-translational modification in PANX1 regulation.

S-Nitrosylation: S-Nitrosylation, the covalent attachment of a nitric oxide group to cysteine residues, has been shown to modulate the activity of various proteins. While direct evidence of S-nitrosylation on PANX1 is lacking, this modification could potentially impact PANX1 function.

How else might Src kinase be involved in the regulation of PANX1 channel opening and closing in various cellular contexts if it is not directly phosphorylating PANX1?

Although the study suggests that Src kinase may not directly phosphorylate PANX1, Src kinase could still be involved in the regulation of PANX1 channel opening and closing through alternative mechanisms. Some potential ways Src kinase might influence PANX1 activity include:

Protein-Protein Interactions: Src kinase could interact with other proteins that directly regulate PANX1 activity. By forming signaling complexes with PANX1-interacting proteins, Src kinase may indirectly modulate PANX1 channel function.

Signaling Pathway Modulation: Src kinase may activate downstream signaling pathways that converge on PANX1 regulation. By influencing the activity of key signaling molecules involved in PANX1 activation, Src kinase could indirectly impact PANX1 channel opening and closing.

Membrane Receptor Crosstalk: Src kinase may mediate crosstalk between membrane receptors and PANX1. By modulating the activity of receptors that signal to PANX1, Src kinase could indirectly regulate PANX1 channel function in response to extracellular stimuli.

Structural Changes: Src kinase activity could induce conformational changes in PANX1 or its interacting partners, altering the accessibility or function of the channel. These structural modifications could impact PANX1 channel opening and closing dynamics.

How might the findings from this study impact the development of pharmacological agents targeting the PANX1 channel for the treatment of PANX1-associated diseases?

The findings from this study have significant implications for the development of pharmacological agents targeting the PANX1 channel for the treatment of PANX1-associated diseases. Some ways in which these findings might impact drug development include:

Target Validation: The study calls into question the existing paradigm of tyrosine phosphorylation-dependent activation of PANX1 by Src kinase. Therefore, drug development efforts targeting PANX1 phosphorylation by Src may need to be reevaluated based on the new understanding that Src may not directly phosphorylate PANX1.

Alternative Targets: With the knowledge that Src kinase may not directly phosphorylate PANX1, drug developers may need to explore alternative targets or pathways for modulating PANX1 activity. Identifying novel targets or regulatory mechanisms could lead to the development of more effective pharmacological agents for PANX1-associated diseases.

Combination Therapies: The study highlights the complexity of PANX1 regulation and the involvement of multiple signaling pathways. This suggests that combination therapies targeting different aspects of PANX1 regulation, beyond Src-mediated phosphorylation, may be more effective in treating PANX1-associated diseases.

Precision Medicine: Understanding the specific post-translational modifications and regulatory mechanisms of PANX1 could enable the development of precision medicine approaches tailored to individual patients. By targeting specific PANX1 regulatory pathways based on patient-specific profiles, personalized treatment strategies could be developed for PANX1-related conditions.