Protein kinase A phosphorylation potentiates cystic fibrosis transmembrane conductance regulator gating by relieving autoinhibition on the stimulatory C terminus of the regulatory domain

6Citations
Citations of this article
10Readers
Mendeley users who have this article in their library.

Abstract

Cystic fibrosis transmembrane conductance regulator (CFTR) is a chloride channel activated by protein kinase A (PKA) phosphorylation on the regulatory (R) domain. Phosphorylation at several R domain residues stimulates ATP-dependent channel openings and closings, termed channel gating. To explore the protein segment responsible for channel potentiation and PKA-dependent activation, deletion mutations were constructed by removing one to three protein segments of the R domain including residues 708 - 759 (ΔR708 -759), R760 -783, and R784 - 835, each of which contains one or two PKA phosphorylation sites. Deletion of R708 -759 or R760 -783 had little effect on CFTR gating, whereas all mutations lacking R784 - 835 reduced CFTR activity by decreasing the mean burst duration and increasing the interburst interval (IBI). The data suggest that R784 - 835 plays a major role in stimulating CFTR gating. For ATP-associated regulation, ΔR784 - 835 had minor impact on gating potentiation by 2'dATP, CaATP, and pyrophosphate. Interestingly, introducing a phosphorylated peptide matching R809 - 835 shortened the IBI of ΔR708 - 835-CFTR. Consistently, ΔR815- 835, but not ΔR784 - 814, enhanced IBI, whereas both reduced mean burst duration. These data suggest that the entirety of R784 - 835 is required for stabilizing the open state of CFTR; however, R815- 835, through interactions with the channel, is dominant for enhancing the opening rate. Of note, PKA markedly decreased the IBI of ΔR708 -783-CFTR. Conversely, the IBI of ΔR708 - 814-CFTR was short and PKA-independent. These data reveal that for stimulating CFTR gating, PKA phosphorylation may relieve R784 - 814-mediated autoinhibition that prevents IBI shortening by R815- 835. This mechanism may elucidate how the R domain potentiates channel gating and may unveil CFTR stimulation by other protein kinases.

Cite

CITATION STYLE

APA

Chen, J. H. (2020). Protein kinase A phosphorylation potentiates cystic fibrosis transmembrane conductance regulator gating by relieving autoinhibition on the stimulatory C terminus of the regulatory domain. Journal of Biological Chemistry, 295(14), 4577–4590. https://doi.org/10.1074/jbc.RA119.008427

Register to see more suggestions

Mendeley helps you to discover research relevant for your work.

Already have an account?

Save time finding and organizing research with Mendeley

Sign up for free