Functional identification of protein phosphatase 1-binding consensus residues in NBCe1-B.
10.4196/kjpp.2018.22.1.91
- Author:
Kyu Pil LEE
1
;
Hyun Jin KIM
;
Dongki YANG
Author Information
1. Laboratory of Physiology, College of Veterinary Medicine, Chungnam National University, Daejeon 34134, Korea.
- Publication Type:Original Article
- Keywords:
HCO₃⁻ secretion;
IRBIT;
NBCe1-B;
Protein phosphatase 1;
SPAK;
WNK
- MeSH:
Amino Acids;
Catalytic Domain;
Consensus*;
Hydrogen-Ion Concentration;
Immunoprecipitation;
Mutagenesis, Site-Directed;
Protein Phosphatase 1;
Signal Transduction
- From:The Korean Journal of Physiology and Pharmacology
2018;22(1):91-99
- CountryRepublic of Korea
- Language:English
-
Abstract:
Protein phosphatase 1 (PP1) is involved in various signal transduction mechanisms as an extensive regulator. The PP1 catalytic subunit (PP1c) recognizes and binds to PP1-binding consensus residues (FxxR/KxR/K) in NBCe1-B. Consequently, we focused on identifying the function of the PP1-binding consensus residue, ⁹²²FMDRLK⁹²⁷ , in NBCe1-B. Using site-directed mutagenesis and co-immunoprecipitation assays, we revealed that in cases where the residues were substituted (F922A, R925A, and K927A) or deleted (deletion of amino acids 922–927), NBCe1-B mutants inhibited PP1 binding to NBCe1-B. Additionally, by recording the intracellular pH, we found that PP1-binding consensus residues in NBCe1-B were not only critical for NBCe1-B activity, but also relevant to its surface expression level. Therefore, we reported that NBCe1-B, as a substrate of PP1, contains these residues in the C-terminal region and that the direct interaction between NBCe1-B and PP1 is functionally critical in controlling the regulation of the HCO₃⁻ transport. These results suggested that like IRBIT, PP1 was another novel regulator of HCO₃⁻ secretion in several types of epithelia.
