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Active zone protein CAST is a component of conventional and ribbon synapses in mouse retina
Author(s) -
DeguchiTawarada Maki,
Inoue Eiji,
TakaoRikitsu Etsuko,
Inoue Marie,
Kitajima Isao,
Ohtsuka Toshihisa,
Takai Yoshimi
Publication year - 2006
Publication title -
journal of comparative neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.855
H-Index - 209
eISSN - 1096-9861
pISSN - 0021-9967
DOI - 10.1002/cne.20893
Subject(s) - biology , retina , component (thermodynamics) , ribbon synapse , neuroscience , ribbon , active zone , synapse , anatomy , microbiology and biotechnology , materials science , genetics , vesicle , membrane , synaptic vesicle , physics , composite material , thermodynamics
CAST is a novel cytomatrix at the active zone (CAZ)‐associated protein. In conventional brain synapses, CAST forms a large molecular complex with other CAZ proteins, including RIM, Munc13‐1, Bassoon, and Piccolo. Here we investigated the distribution of CAST and its structurally related protein, ELKS, in mouse retina. Immunofluorescence analyses revealed that CAST and ELKS showed punctate signals in the outer and inner plexiform layers of the retina that were well‐colocalized with those of Bassoon and RIM. Both proteins were found presynaptically at glutamatergic ribbon synapses, and at conventional GABAergic and glycinergic synapses. Moreover, immunoelectron microscopy revealed that CAST, like Bassoon and RIM, localized at the base of synaptic ribbons, whereas ELKS localized around the ribbons. Both proteins also localized in the vicinity of the presynaptic plasma membrane of conventional synapses in the retina. These results indicated that CAST and ELKS were novel components of the presynaptic apparatus of mouse retina. J. Comp. Neurol. 495:480–496, 2006. © 2006 Wiley‐Liss, Inc.