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IQ‐ArfGEF/BRAG1 is associated with synaptic ribbons in the mouse retina
Author(s) -
Katsumata Osamu,
Ohara Naoki,
Tamaki Hideaki,
Niimura Tomoko,
Naganuma Hideaki,
Watanabe Masahiko,
Sakagami Hiroyuki
Publication year - 2009
Publication title -
european journal of neuroscience
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.346
H-Index - 206
eISSN - 1460-9568
pISSN - 0953-816X
DOI - 10.1111/j.1460-9568.2009.06943.x
Subject(s) - retina , immunoelectron microscopy , outer plexiform layer , immunoprecipitation , microbiology and biotechnology , biology , synapse , retinal , guanine nucleotide exchange factor , chemistry , biophysics , neuroscience , immunohistochemistry , biochemistry , gene , immunology , signal transduction
IQ‐ArfGEF/BRAG1 is a guanine nucleotide exchange factor for ADP ribosylation factors (Arfs), which are implicated in membrane trafficking and actin cytoskeleton dynamics. In this study, we examined the immunohistochemical localization of IQ‐ArfGEF/BRAG1 in the adult mouse retina using light and electron microscopy. IQ‐ArfGEF/BRAG1 was distributed in a punctate manner and colocalized well with RIBEYE in both the outer and inner plexiform layers. Immunoelectron microscopic analysis showed that IQ‐ArfGEF/BRAG1 was localized at the synaptic ribbons of photoreceptors. When heterologously expressed in HeLa cells, IQ‐ArfGEF/BRAG1 was recruited to RIBEYE‐containing clusters and formed an immunoprecipitable complex with RIBEYE. Furthermore, immunoprecipitation analysis showed that anti‐IQ‐ArfGEF/BRAG1 antibody efficiently pulled down RIBEYE from retinal lysates. These findings indicate that IQ‐ArfGEF/BRAG1 is a novel component of retinal synaptic ribbons and forms a protein complex with RIBEYE.