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Published on: February 22, 2014
Mass spectrometric analysis of novel phosphorylation sites in the TRPC4β channel
Ji Eun Lee1, Min-Young Song, Seok Kyo Shin
1Department of Physiology, and Biomedical Science Institute, Kyung Hee University School of Medicine, Seoul 130-701, South Korea.
Rationale:
The transient receptor potential canonical (TRPC) channel 4β is a non-selective cation channel that is regulated by intracellular Ca(2+) and G protein-coupled receptors. Tyrosine phosphorylation of TRPC4β is important in mediating the activity and membrane expression of this channel protein. However, studies of TRPC4β Ser/Thr phosphorylation are lacking.
Methods:
To investigate the phosphorylation sites involved in regulating the diverse functions of TRPC4β in mammalian cells, we used nano-liquid chromatography/tandem mass spectrometry to identify key phosphorylation sites in TRPC4β that was immunopurified from HEK293 cells with monoclonal anti-TRPC4β antibody.
Results:
We identified four phosphorylation sites in the C-terminus of TRPC4β, none of which had been previously reported. Our data show that TRPC4β in mammalian cells is highly phosphorylated under basal conditions at multiple sites, and that a mass spectrometric proteomic technique combined with antibody-based affinity purification is an effective approach to define the phosphorylation sites of TRPC4β channels in mammalian cells.
Conclusions:
These novel phosphorylation sites on TRPC4β may play a potential role in the phosphorylation-mediated regulation of TRPC4β channel activity and function in mammalian cells.
Insights
Researchers identified novel Ser/Thr phosphorylation sites on the TRPC4β channel using mass spectrometry. These findings reveal new regulatory mechanisms for TRPC4β channel activity and function in mammalian cells.
Area of Science:
- Molecular Biology
- Cell Physiology
- Biochemistry
Background:
- Transient receptor potential canonical (TRPC) channel 4β is a non-selective cation channel regulated by intracellular Ca(2+) and G protein-coupled receptors.
- Tyrosine phosphorylation influences TRPC4β activity and membrane expression, but Ser/Thr phosphorylation remains understudied.
Purpose of the Study:
- To identify key Ser/Thr phosphorylation sites on TRPC4β in mammalian cells.
- To investigate the role of these phosphorylation sites in regulating TRPC4β function.
Main Methods:
- Immunopurification of TRPC4β from HEK293 cells using a monoclonal anti-TRPC4β antibody.
- Nano-liquid chromatography/tandem mass spectrometry (nLC-MS/MS) to identify phosphorylation sites.
Main Results:
- Four novel Ser/Thr phosphorylation sites were identified in the C-terminus of TRPC4β.
- TRPC4β exhibits significant basal phosphorylation at multiple sites in mammalian cells.
- The combined approach of mass spectrometry and antibody-based purification effectively defines TRPC4β phosphorylation sites.
Conclusions:
- Newly discovered phosphorylation sites on TRPC4β may regulate channel activity and function.
- These findings provide insights into the phosphorylation-mediated regulation of TRPC4β in mammalian systems.
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