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作者 |
Lee, HH; Nemecek, D; Schindler, C; Smith, WJ; Ghirlando, R; Steven, AC; Bonifacino, JS; Hurley, JH |
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[摘要]:BLOC-1 (biogenesis of lysosome-related organelles complex-1) is critical for melanosome biogenesis and has also been implicated in neurological function and disease. We show that BLOC-1 is an elongated complex that contains one copy each of the eight subunits pallidin, Cappuccino, dysbindin, Snapin, Muted, BLOS1, BLOS2, and BLOS3. The complex appears as a linear chain of eight globular domains, similar to 300 angstrom long and similar to 30 angstrom in diameter. The individual domains are flexibly connected such that the linear chain undergoes bending by as much as 45 degrees. Two stable subcomplexes were defined, pallidin-Cappuccino-BLOS1 and dysbindin-Snapin-BLOS2. Both subcomplexes are 1:1:1 heterotrimers that form extended structures as indicated by their hydrodynamic properties. The two subcomplexes appear to constitute flexible units within the larger BLOC-1 chain, an arrangement conducive to simultaneous interactions with multiple BLOC-1 partners in the course of tubular endosome biogenesis and sorting. |
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