Mental retardation-related protease, motopsin (prss12), binds to the BRICHOS domain of the integral membrane protein 2a
Mental retardation-related protease, motopsin (prss12), binds to the BRICHOS domain of the integral membrane protein 2a
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DOI：
10.1002/cbin.10164
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发表时间：
2014-01-01
影响因子：
3.9
通讯作者：
Yuri, Kazunari
中科院分区：
文献类型：
--
作者：
Mitsui, Shinichi;Osako, Yoji;Yuri, Kazunari
Motopsin （prss12）是一种由神经细胞分泌的马赛克丝氨酸蛋白酶，被认为对认知功能很重要，因为其功能的丧失会导致严重的非综合征性智力迟钝。为了了解motopsin的分子作用，我们使用酵母双杂交系统鉴定了积分膜蛋白2a （Itm2a）是一个与motopsin相互作用的蛋白。下拉实验显示Itm2a的BRICHOS结构域对这种相互作用至关重要。Motopsin和Itm2a在COS细胞和培养的神经元中短暂表达时，在这些细胞中共定位。从这些转染的COS细胞的裂解物中共免疫沉淀这两种蛋白。在出生后第0天至第10天制备的脑裂解液中强烈检测到Itm2a，在此期间大脑中也富含运动蛋白酶蛋白。免疫组织化学检测到Itm2a在脑毛细血管内皮细胞（也表达肌球蛋白II调节轻链[RLC]）和发育中的大脑皮层胶质原纤维酸性蛋白（GFAP）阳性过程中呈斑块状。这些数据提高了分泌的运动酶与发育中的大脑内皮细胞相互作用的可能性。
Motopsin (prss12), a mosaic serine protease secreted by neuronal cells, is believed to be important for cognitive function, as the loss of its function causes severe nonsyndromic mental retardation. To understand the molecular role of motopsin, we identified the integral membrane protein 2a (Itm2a) as a motopsin-interacting protein using a yeast two-hybrid system. A pull-down assay showed that the BRICHOS domain of Itm2a was essential for this interaction. Motopsin and Itm2a co-localized in COS cells and in cultured neurons when transiently expressed in these cells. Both proteins were co-immunoprecipitated from lysates of these transfected COS cells. Itm2a was strongly detected in a brain lysate prepared between postnatal day 0 and 10, during which period motopsin protein was also enriched in the brain. Immunohistochemistry detected Itm2a as patchy spots along endothelial cells of brain capillaries (which also expressed myosin II regulatory light chain [RLC]), and on glial fibrillary acidic protein (GFAP)-positive processes in the developing cerebral cortex. The data raise the possibility that secreted motopsin interacts with endothelial cells in the developing brain.