title: Mental retardation-related protease, motopsin (prss12), binds to the BRICHOS domain of the integral membrane protein 2a.
abstract: 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.
authors: Department of Rehabilitation Sciences, Gunma University Graduate School of Health Sciences, Showa, Maebashi, 371-8514, Japan.
authors: Shinichi
authors: S
authors: Mitsui
authors: Yoji
authors: Y
authors: Osako
authors: Kazunari
authors: K
authors: Yuri
mesh_terms: D000818:Animals; D001921:Brain / Q000378:metabolism; D019556:COS Cells; D002522:Chlorocebus aethiops; D005260:Female; D007150:Immunohistochemistry; D008565:Membrane Proteins / Q000737:chemistry / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D012697:Serine Endopeptidases / Q000378:metabolism*; D020798:Two-Hybrid System Techniques
chemical_list: C117398:Itm2a protein, mouse; D008565:Membrane Proteins; D012697:Serine Endopeptidases; C108493:neurotrypsin
keywords: astrocyte; capillary; developmental disorders; neurotrypsin; serine protease