Okamoto M, Südhof T C
Center for Basic Neuroscience, Department of Molecular Genetics, The University of Texas Southwestern Medical School, Dallas 75235, USA.
Eur J Cell Biol. 1998 Nov;77(3):161-5. doi: 10.1016/S0171-9335(98)80103-9.
Mint 1 and 2 are proteins that bind to munc18-1, an essential component of the synaptic vesicle fusion machinery, and are detectably expressed only in neurons [Okamoto and Südhof, J. Biol. Chem. 272, 31459-31464 (1997)]. Mint 1 and 2 are composed of a variable N-terminal region that includes a conserved munc18-1-binding site, and a constant C-terminal region that contains one PTB and two PDZ domains. We have now identified a third mint isoform, mint 3. Similar to mint 1 and 2, the C-terminal half of mint 3 is composed of one PTB domain and two PDZ domains. However, in contrast to mint 1 and 2, mint 3 lacks an N-terminal munc18-binding domain and does not interact with munc18-1 in yeast two-hybrid assays. Mint 3 is ubiquitously expressed in all tissues, with lowest levels in brain and testis whereas mint 1 and 2 appear to be brain-specific. Our data suggest that mints form a diverse family of proteins with specialized neuronal and ubiquitous isoforms.
Mint 1和Mint 2是与munc18-1结合的蛋白质，munc18-1是突触小泡融合机制的一个重要组成部分，且仅在神经元中可检测到表达[冈本和祖德霍夫，《生物化学杂志》272，31459 - 31464(1997)]。Mint 1和Mint 2由一个可变的N端区域和一个恒定的C端区域组成，可变的N端区域包含一个保守的munc18-1结合位点，恒定的C端区域包含一个PTB结构域和两个PDZ结构域。我们现在鉴定出了第三种mint异构体，即mint 3。与Mint 1和Mint 2相似，mint 3的C端一半由一个PTB结构域和两个PDZ结构域组成。然而，与Mint 1和Mint 2不同的是，mint 3缺乏N端的munc18结合结构域，并且在酵母双杂交试验中不与munc18-1相互作用。mint 3在所有组织中普遍表达，在脑和睾丸中的表达水平最低，而Mint 1和Mint 2似乎是脑特异性的。我们的数据表明，mints形成了一个多样化的蛋白质家族，具有专门的神经元异构体和普遍存在的异构体。
