Synaptic localization of neuroligin 2 in the rodent retina: comparative study with the dystroglycan-containing complex.
Several recent studies have shown that neuroligin 2 (NL2), a component of the cell adhesion neurexins-neuroligins complex, is localized postsynaptically at hippocampal and other inhibitory synapses throughout the brain. Other studies have shown that components of the dystroglycan complex are also localized at a subset of inhibitory synapses and are coexpressed with NL2 in brain. These data prompted us to undertake a comparative study between the localization of NL2 and the dystroglycan complex in the rodent retina. First, we determined that NL2 mRNA is expressed both in the inner and in the outer nuclear layers. Second, we found that NL2 is localized both in the inner and in the outer synaptic plexiform layers. In the latter, the horseshoe-shaped pattern of NL2 and its extensive colocalization with RIM2, a component of the presynaptic active zone at ribbon synapses, argue that NL2 is localized presynaptically at photoreceptor terminals. Third, comparison of NL2 and the dystroglycan complex distribution patterns reveals that, despite their coexpression in the outer plexiform layer, they are spatially segregated within distinct domains of the photoreceptor terminals, where NL2 is selectively associated with the active zone and the dystroglycan complex is distally distributed in the lateral regions. Finally, we report that the dystroglycan deficiency in the mdx(3cv) mouse does not alter NL2 localization in the outer plexiform layer. These data show that the NL2- and dystroglycan-containing complexes are differentially localized in the presynaptic photoreceptor terminals and suggest that they may serve distinct functions in retina.
Lui
Leona
L
Department of Cellular and Physiological Sciences, Life Sciences Institute, The University of British Columbia, Vancouver, British Columbia, Canada.
Levinson
Joshua N
JN
Noël
Geoffroy
G
Handrigan
Gregory R
GR
Richman
Joy M
JM
El-Husseini
Alaa
A
Moukhles
Hakima
H
D000818:Animals; D015816:Cell Adhesion Molecules, Neuronal; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000166:cytology; D000076122:Disks Large Homolog 4 Protein; D049030:Dystroglycans / Q000235:genetics / Q000378:metabolism*; D004622:Embryo, Mammalian; D051528:Guanylate Kinases; D006624:Hippocampus / Q000166:cytology; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D018101:Mice, Inbred mdx; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism*; D009474:Neurons / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D012160:Retina / Q000166:cytology*; D013569:Synapses / Q000378:metabolism*; D016708:Synaptophysin / Q000378:metabolism; D050598:Vesicular Glutamate Transport Protein 1 / Q000378:metabolism; D050495:Vesicular Inhibitory Amino Acid Transport Proteins / Q000378:metabolism; D020692:rab3 GTP-Binding Proteins / Q000378:metabolism
D015816:Cell Adhesion Molecules, Neuronal; D000076122:Disks Large Homolog 4 Protein; C501447:Dlg4 protein, mouse; D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; D016708:Synaptophysin; D050598:Vesicular Glutamate Transport Protein 1; D050495:Vesicular Inhibitory Amino Acid Transport Proteins; C492244:Viaat protein, mouse; C098003:neuroligin 2; D049030:Dystroglycans; D051528:Guanylate Kinases; C475524:Rim2 protein, mouse; D020692:rab3 GTP-Binding Proteins