■Bai3 expressed in the cochlea plays an important role in auditory function（Int J Mol Sci）2023.12.4
Saegusa C, Kakegawa W, Miura E, Aimi T, Mogi S, Harada T, Yamashita T, Yuzaki M, Fujioka M. Brain-Specific Angiogenesis Inhibitor 3 Is Expressed in the Cochlea and Is Necessary for Hearing Function in Mice. Int J Mol Sci 24:17092 (2023).

Mammalian inner hair cells、It converts sound into electrical signals in the cochlea, which is essential for hearing function.。The "pillar cells" located between the inner and outer hair cells are、Fluid vibrations transmitted by outer hair cells and、It is thought that capturing the vibrations of the basilar membrane leads to frequency-specific sound perception.、The mechanism of pillar cell development and maintenance was unknown.。In this study、Bai3, an adhesive G protein-coupled receptor, is expressed in pillar cells in adult mice.、We found that Bai3 knockout mice exhibit abnormal formation of pillar cells and hearing loss.。These results are、suggests that Bai3 contributes to normal auditory function via pillar cell function。This study、Dr. Fujioka transferred from Keio Otolaryngology to Kitasato University.、This is the result of joint research with Mr. Saegusa.。

C1ql1-Bai3 signaling regulates resynapse formation of climbing fibers after maturation（Mol Brain）2023.7.25
Aimi T, Keiko Matsuda K, Yuzaki M. C1ql1-Bai3 signaling is necessary for climbing fiber synapse formation in mature Purkinje cells in coordination with neuronal activity. Molecular Brain 16:61 (2023).

Cerebellar Purkinje cells form multiple climbing fibers and synapses when young、Unnecessary synapses are pruned during development, except for one climbing fiber。In this paper、climbing fiber：1 Purkinje cell：1In the mature cerebellum, which has established the mode of control of、By increasing the expression level of C1ql1 and Bai3、Purkinje cells create multiple climbing fibers and synapses again、Climbing fibers usually branch in the anterior-posterior direction,、Newly formed synapses originate from branches diverging inwards and outwards、They discovered that the presence of electrical activity in climbing fibers and Purkinje cells is necessary for new synapse formation.。Even when the GluD2 glutamate receptor is knocked out after maturation,、It is known that the internal and external branches of multiple climbing fibers re-synapse with Purkinje cells.、We also found that this phenomenon is also dependent on C1ql1-Bai3 signaling。

Rab21 regulates caveolin-1-mediated endocytosis and promotes shearing of immature neurites（EMBO Rep）2023.1.25

Shikanai M, This S, Nishimura YV, Akagawa R, Fukuda M, Yuzaki M, Nabeshima YI, Kawauchi T. Rab21 regulates caveolin-1-mediated endocytic trafficking to promote immature neurite pruning. EMBO Rep. e54701, 2023. doi: 10.15252/embr. 202254701
Transmembrane proteins are internalized by clathrin- and caveolin-dependent endocytosis。Both pathways converge on early endosomes、It is thought to have Rab5, a low-molecular-weight GTPase, as a common regulatory factor。However、In this paper,、The clathrin- and caveolin-mediated endocytic pathway is、proceed in parallel in early endosomes、It was clarified that each showed different molecular control and physiological functions。This research is a further development of the work of Mr. Shikauchi and Mr. Kawauchi conducted at Yuzaki Lab.。