Browsing by Author "Su, Kaiwen"

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    LRRTM1 underlies synaptic convergence in visual thalamus
    Monavarfeshani, Aboozar; Stanton, Gail; Van Name, Jonathan; Su, Kaiwen; Mills, William A. III; Swilling, Kenya; Kerr, Alicia; Huebschman, Natalie A.; Su, Jianmin; Fox, Michael A. (eLife, 2018-02-09)
    It has long been thought that the mammalian visual system is organized into parallel pathways, with incoming visual signals being parsed in the retina based on feature (e.g. color, contrast and motion) and then transmitted to the brain in unmixed, feature-specific channels. To faithfully convey feature-specific information from retina to cortex, thalamic relay cells must receive inputs from only a small number of functionally similar retinal ganglion cells. However, recent studies challenged this by revealing substantial levels of retinal convergence onto relay cells. Here, we sought to identify mechanisms responsible for the assembly of such convergence. Using an unbiased transcriptomics approach and targeted mutant mice, we discovered a critical role for the synaptic adhesion molecule Leucine Rich Repeat Transmembrane Neuronal 1 (LRRTM1) in the emergence of retinothalamic convergence. Importantly, LRRTM1 mutant mice display impairment in visual behaviors, suggesting a functional role of retinothalamic convergence in vision.
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    Target-Derived Matricryptins Organize Cerebellar Synapse Formation through _3_1 Integrins
    Su, Jianmin; Stenbjorn, Renee S.; Gorse, Karen; Su, Kaiwen; Hauser, Kurt F.; Ricard-Blum, Sylvie; Pihlajaniemi, Taina; Fox, Michael A. (Cell, 2012)
    Trans-synaptic organizing cues must be passed between synaptic partners for synapses to properly form. Much of our understanding of this process stems from studies at the neuromuscular junction, where target-derived growth factors, extracellular matrix (ECM) molecules, and matricryptins (proteolytically released fragments of ECM molecules) are all essential for the formation and maintenance of motor nerve terminals. While growth factors and ECM molecules also contribute to the formation of brain synapses, it remains unclear whether synaptic roles exist for matricryptins in the mammalian brain. We report that collagen XVIII and its matricryptin endostatin are generated by cerebellar Purkinje cells and are necessary for the organization of climbing fiber terminals in these neurons. Moreover, endostatin is sufficient to induce climbing fiber terminal formation in vitro by binding and signaling through _3_1 integrins. Taken together, these studies reveal roles for both matricryptins and integrins in the organization of brain synapses.