PMID- 27502273
OWN - NLM
STAT- MEDLINE
DCOM- 20170519
LR  - 20210205
IS  - 1083-351X (Electronic)
IS  - 0021-9258 (Print)
IS  - 0021-9258 (Linking)
VI  - 291
IP  - 39
DP  - 2016 Sep 23
TI  - The Human Ether-a-go-go-related Gene (hERG) Potassium Channel Represents an 
      Unusual Target for Protease-mediated Damage.
PG  - 20387-401
LID - 10.1074/jbc.M116.743138 [doi]
AB  - The human ether-a-go-go-related gene (hERG) encodes the pore-forming subunit of 
      the rapidly activating delayed rectifier potassium channel (IKr), which is 
      important for cardiac repolarization. Dysfunction of hERG causes long QT syndrome 
      and sudden death, which occur in patients with cardiac ischemia. Cardiac ischemia 
      is also associated with activation, up-regulation, and secretion of various 
      proteolytic enzymes. Here, using whole-cell patch clamp and Western blotting 
      analysis, we demonstrate that the hERG/IKr channel was selectively cleaved by the 
      serine protease, proteinase K (PK). Using molecular biology techniques including 
      making a chimeric channel between protease-sensitive hERG and insensitive human 
      ether-a-go-go (hEAG), as well as application of the scorpion toxin BeKm-1, we 
      identified that the S5-pore linker of hERG is the target domain for proteinase K 
      cleavage. To investigate the physiological relevance of the unique susceptibility 
      of hERG to proteases, we show that cardiac ischemia in a rabbit model was 
      associated with a reduction in mature ERG expression and an increase in the 
      expression of several proteases, including calpain. Using cell biology 
      approaches, we found that calpain-1 was actively released into the extracellular 
      milieu and cleaved hERG at the S5-pore linker. Using protease cleavage-predicting 
      software and site-directed mutagenesis, we identified that calpain-1 cleaves hERG 
      at position Gly-603 in the S5-pore linker of hERG. Clarification of 
      protease-mediated damage of hERG extends our understanding of hERG regulation. 
      Damage of hERG mediated by proteases such as calpain may contribute to 
      ischemia-associated QT prolongation and sudden cardiac death.
CI  - (c) 2016 by The American Society for Biochemistry and Molecular Biology, Inc.
FAU - Lamothe, Shawn M
AU  - Lamothe SM
AD  - From the Department of Biomedical and Molecular Sciences, Queen's University, 
      Kingston, Ontario K7L 3N6, Canada.
FAU - Guo, Jun
AU  - Guo J
AD  - From the Department of Biomedical and Molecular Sciences, Queen's University, 
      Kingston, Ontario K7L 3N6, Canada.
FAU - Li, Wentao
AU  - Li W
AD  - From the Department of Biomedical and Molecular Sciences, Queen's University, 
      Kingston, Ontario K7L 3N6, Canada.
FAU - Yang, Tonghua
AU  - Yang T
AD  - From the Department of Biomedical and Molecular Sciences, Queen's University, 
      Kingston, Ontario K7L 3N6, Canada.
FAU - Zhang, Shetuan
AU  - Zhang S
AD  - From the Department of Biomedical and Molecular Sciences, Queen's University, 
      Kingston, Ontario K7L 3N6, Canada shetuan.zhang@queensu.ca.
LA  - eng
GR  - MOP 72911/CIHR/Canada
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
DEP - 20160808
PL  - United States
TA  - J Biol Chem
JT  - The Journal of biological chemistry
JID - 2985121R
RN  - 0 (BeKm-1 toxin)
RN  - 0 (ERG1 Potassium Channel)
RN  - 0 (KCNH2 protein, human)
RN  - 0 (Scorpion Venoms)
RN  - EC 3.4.21.64 (Endopeptidase K)
RN  - EC 3.4.22.- (Calpain)
RN  - EC 3.4.22.52 (CAPN1 protein, human)
SB  - IM
MH  - Animals
MH  - Calpain/biosynthesis/chemistry/genetics
MH  - ERG1 Potassium Channel/chemistry/genetics/*metabolism
MH  - Endopeptidase K/chemistry
MH  - HEK293 Cells
MH  - Humans
MH  - Male
MH  - Myocardial Ischemia/genetics/*metabolism
MH  - *Proteolysis
MH  - Rabbits
MH  - Scorpion Venoms/pharmacology
PMC - PMC5034037
OTO - NOTNLM
OT  - cell surface protein
OT  - electrophysiology
OT  - hERG
OT  - ion channel
OT  - patch clamp
OT  - potassium channel
OT  - protease
EDAT- 2016/08/10 06:00
MHDA- 2017/05/20 06:00
PMCR- 2017/09/23
CRDT- 2016/08/10 06:00
PHST- 2016/06/10 00:00 [received]
PHST- 2016/08/10 06:00 [entrez]
PHST- 2016/08/10 06:00 [pubmed]
PHST- 2017/05/20 06:00 [medline]
PHST- 2017/09/23 00:00 [pmc-release]
AID - S0021-9258(20)35915-9 [pii]
AID - M116.743138 [pii]
AID - 10.1074/jbc.M116.743138 [doi]
PST - ppublish
SO  - J Biol Chem. 2016 Sep 23;291(39):20387-401. doi: 10.1074/jbc.M116.743138. Epub 
      2016 Aug 8.