Vol. 275, Issue 6, H1963-H1970, December 1998
Isolation and characterization of the human gene encoding
Ito: further
diversity by alternative mRNA splicing
Wei
Kong1,
Sunny
Po1,
Toshio
Yamagishi1,
M. Dominique
Ashen1,
Gail
Stetten2, and
Gordon F.
Tomaselli1
1 Department of Medicine,
Section of Molecular and Cellular Cardiology, and
2 Department of Gynecology and
Obstetrics, Johns Hopkins University, Baltimore, Maryland 21205
The transient
outward K+ current
(Ito) in the
heart is responsible for the initial phase of repolarization and for
setting the plateau voltage of the ventricular action potential.
Recently, Kv4.3 has emerged as the leading candidate 
-subunit gene
that underlies
Ito in larger
mammals such as dogs and humans. We have cloned the human Kv4.3 homolog
and describe a carboxyl-terminal splice variant that inserts 19 amino
acids with a consensus protein kinase C (PKC) phosphorylation site into
the protein after the last membrane-spanning segment. The coding region
of Kv4.3 is comprised of at least five exons and is located on
chromosome 1p13.3. In the basal state the basic biophysical properties
of both of the splice variants are identical.
potassium channel; Kv4.2; Kv4.3; Xenopus oocytes; heterologous
expression; fluorescence in situ hybridization; chromosome 1
