title: Protein-4.1G-Mediated Membrane Trafficking Is Essential for Correct Rod Synaptic Location in the Retina and for Normal Visual Function.
abstract: In vertebrate retinal development, the axonal terminals of retinal neurons make synaptic contacts within narrow fixed regions, and these locations are maintained thereafter. However, the mechanisms and biological logic of the organization of these fixed synapse locations are poorly understood. We show here that a membrane scaffold protein, 4.1G, is highly expressed in retinal photoreceptors and is essential for the arrangement of their correct synapse location. The 4.1G-deficient retina exhibits mislocalization of photoreceptor terminals, although their synaptic connections are normally formed. The 4.1G protein binds to the AP3B2 protein, which is involved in neuronal membrane trafficking, and promotes neurite extension in an AP3B2-dependent manner. 4.1G mutant mice showed visual acuity impairments in an optokinetic response, suggesting that correct synapse location is required for normal visual function. Taken together, the data in this study provide insight into the mechanism and importance of proper synapse location in neural circuit formation.
authors: Laboratory for Molecular and Developmental Biology, Institute for Protein Research, Osaka University, Suita, Osaka 565-0871, Japan; JST, CREST, Suita, Osaka 565-0871, Japan.
authors: Rikako
authors: R
authors: Sanuki
authors: Laboratory for Molecular and Developmental Biology, Institute for Protein Research, Osaka University, Suita, Osaka 565-0871, Japan; JST, CREST, Suita, Osaka 565-0871, Japan.
authors: Satoshi
authors: S
authors: Watanabe
authors: Laboratory for Molecular and Developmental Biology, Institute for Protein Research, Osaka University, Suita, Osaka 565-0871, Japan; JST, CREST, Suita, Osaka 565-0871, Japan.
authors: Yuko
authors: Y
authors: Sugita
authors: Laboratory for Molecular and Developmental Biology, Institute for Protein Research, Osaka University, Suita, Osaka 565-0871, Japan; JST, CREST, Suita, Osaka 565-0871, Japan.
authors: Shoichi
authors: S
authors: Irie
authors: Laboratory for Molecular and Developmental Biology, Institute for Protein Research, Osaka University, Suita, Osaka 565-0871, Japan; JST, CREST, Suita, Osaka 565-0871, Japan.
authors: Takashi
authors: T
authors: Kozuka
authors: Laboratory for Molecular and Developmental Biology, Institute for Protein Research, Osaka University, Suita, Osaka 565-0871, Japan; JST, CREST, Suita, Osaka 565-0871, Japan.
authors: Mariko
authors: M
authors: Shimada
authors: Department of Ophthalmology, Nagoya University Graduate School of Medicine, Showa-ku, Nagoya 466-8550, Japan.
authors: Shinji
authors: S
authors: Ueno
authors: Structural Biology Center, Graduate School of Science, Nagoya University, Chikusa-ku, Nagoya 464-8603, Japan.
authors: Jiro
authors: J
authors: Usukura
authors: Laboratory for Molecular and Developmental Biology, Institute for Protein Research, Osaka University, Suita, Osaka 565-0871, Japan; JST, CREST, Suita, Osaka 565-0871, Japan. Electronic address: takahisa.furukawa@protein.osaka-u.ac.jp.
authors: Takahisa
authors: T
authors: Furukawa