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Updated: Aug 15, 2026

Characterization at the Molecular Level using Robust Biochemical Approaches of a New Kinase Protein
Published on: June 30, 2019
MPS-1 is a K+ channel beta-subunit and a serine/threonine kinase
Shi-Qing Cai1, Leonardo Hernandez, Yi Wang
1University of Medicine and Dentistry of New Jersey, Robert Wood Johnson Medical School, Department of Physiology and Biophysics, 683 Hoes Lane, Piscataway, New Jersey 08854, USA.
Abstract:
We report the first example of a K+ channel beta-subunit that is also a serine/threonine kinase. MPS-1 is a single-transmembrane domain protein that coassembles with voltage-gated K+ channel KVS-1 in the nervous system of the nematode Caenorhabditis elegans. Biochemical analysis shows that MPS-1 can phosphorylate KVS-1 and other substrates. Electrophysiological analysis in Chinese hamster ovary (CHO) cells demonstrates that MPS-1 activity leads to a significant decrease in the macroscopic current. Single-channel analysis and biotinylation assays indicate that MPS-1 reduces the macroscopic current by lowering the open probability of the channel. These data are consistent with a model that predicts that the MPS-1-dependent phosphorylation of KVS-1 sustains cell excitability by controlling K+ flux.
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