Diversity between mammalian tolloid proteinases: Oligomerisation and non-catalytic domains influence activity and specificity.
Diversity between mammalian tolloid proteinases: Oligomerisation and non-catalytic domains influence activity and specificity.
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DOI：
10.1038/srep21456
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发表时间：
2016-02-23
影响因子：
4.6
通讯作者：
Baldock C
中科院分区：
文献类型：
--
作者：
Bayley CP;Ruiz Nivia HD;Dajani R;Jowitt TA;Collins RF;Rada H;Bird LE;Baldock C
哺乳动物金属蛋白酶tolloid家族对于组织图案化和细胞外基质组装至关重要。该家族的四个成员：骨形态发生蛋白-1（BMP-1）、哺乳动物tolloid（mostly）、tolloid-like（TLL）-1和TLL-2在其底物特异性和活性水平上不同，尽管共享相似的结构域组织。我们以前已经描述了一个模型的底物排斥二聚体来解释的差异，在活动的单体BMP-1和二聚体的mostatin和TLL-1。在这里，我们表明，TLL-2，tolloid家族的最不活跃的成员，主要是单体在溶液中，因此，它似乎不太可能通过二聚化的底物排斥是一种机制，用于调节TLL-2的活性。X-射线散射和电子显微镜结构和生物物理分析揭示了在不存在钙的情况下单体和灵活性的细长形状。此外，我们表明，TLL-2可以在体外切割脊索蛋白，类似于其他哺乳动物tolloids，但截短形式的TLL-2模仿BMP-1不能切割脊索蛋白。然而，所有哺乳动物tolloids的N-和C-末端非催化结构域都以高亲和力结合脊索蛋白。tolloid家族中底物特异性和活性的潜在机制是复杂的，家族成员之间存在差异，并依赖于多聚化和底物相互作用。
The mammalian tolloid family of metalloproteinases is essential for tissue patterning and extracellular matrix assembly. The four members of the family: bone morphogenetic protein-1 (BMP-1), mammalian tolloid (mTLD), tolloid-like (TLL)-1 and TLL-2 differ in their substrate specificity and activity levels, despite sharing similar domain organization. We have previously described a model of substrate exclusion by dimerisation to explain differences in the activities of monomeric BMP-1 and dimers of mTLD and TLL-1. Here we show that TLL-2, the least active member of the tolloid family, is predominantly monomeric in solution, therefore it appears unlikely that substrate exclusion via dimerisation is a mechanism for regulating TLL-2 activity. X-ray scattering and electron microscopy structural and biophysical analyses reveal an elongated shape for the monomer and flexibility in the absence of calcium. Furthermore, we show that TLL-2 can cleave chordin in vitro, similar to other mammalian tolloids, but truncated forms of TLL-2 mimicking BMP-1 are unable to cleave chordin. However, both the N- and C-terminal non-catalytic domains from all mammalian tolloids bind chordin with high affinity. The mechanisms underlying substrate specificity and activity in the tolloid family are complex with variation between family members and depend on both multimerisation and substrate interaction.