RT Journal Article
SR Electronic
T1 Deactivation of Phosphorylated and Nonphosphorylated Rhodopsin by Arrestin Splice Variants
JF The Journal of Neuroscience
JO J. Neurosci.
FD Society for Neuroscience
SP 1036
OP 1044
DO 10.1523/JNEUROSCI.3301-05.2006
VO 26
IS 3
A1 Marie E. Burns
A1 Ana Mendez
A1 Ching-Kang Chen
A1 Aileen Almuete
A1 Nidia Quillinan
A1 Melvin I. Simon
A1 Denis A. Baylor
A1 Jeannie Chen
YR 2006
UL http://www.jneurosci.org/content/26/3/1036.abstract
AB Arrestins constitute a family of small cytoplasmic proteins that mediate deactivation of G-protein-coupled receptors (GPCRs) and are known to be essential for cascade inactivation and receptor desensitization. Alternative splicing produces an array of arrestin gene products that have widely different specificities for their cognate receptors in vitro, but the differential functions of these splice variants in vivo are essentially unknown. Bovine rod photoreceptors express two splice variants of visual arrestin (p44 and p48) that display different affinities for the GPCR rhodopsin. To determine the functions of these splice variants in intact cells, we expressed a transgene encoding either a truncated form of murine arrestin (mArr1–369, or m44) or the long (p48) isoform in mouse rods lacking endogenous arrestin (Arr–/–). Morphological analysis showed that expression of either variant attenuated the light-induced degeneration that is thought to result from excessive cascade activity in Arr–/–rods. Suction electrode recordings from individual rods indicated that the expression of either m44 or p48 splice variants could restore normal kinetics to Arr–/– dim flash responses, indicating that both isoforms can bind to and quench phosphorylated rhodopsin rapidly. To our surprise, only the full-length variant was able to alter the kinetics of responses in rods lacking both arrestin and rhodopsin kinase, indicating that p48 can also quench the activity of nonphosphorylated rhodopsin.