Distinguishing between calpain heterodimerization and homodimerization
Distinguishing between calpain heterodimerization and homodimerization
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钙蛋白酶异二聚化和同二聚化的区别
DOI：
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发表时间：
2009
期刊：
影响因子：
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通讯作者：
P. Davies
中科院分区：
文献类型：
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作者：
R. Ravulapalli;R. Campbell;S. Gauthier;S. Dhe;P. Davies
两种主要的哺乳动物钙蛋白酶，1和2，是一个大的80 kDa和一个小的28 kDa的亚基，在酶激活过程中结合多个钙离子的异二聚体。 这些细胞内半胱氨酸蛋白酶的两个亚基之间的主要接触是通过其C末端五EF手（PEF）结构域的第五EF手的配对。从模型研究和晶体结构的观察来看，为什么这些钙蛋白酶与小亚基形成异源二聚体而不是大亚基的同源二聚体（如钙蛋白酶3（p94）所示）并不明显。 因此，我们使用了差异标记系统来确定哪些其他含PEF结构域的钙蛋白酶形成异二聚体，哪些形成同源二聚体。His6标记的钙蛋白酶1、3、9和13的PEF结构域与已经用抗冻蛋白标记的小亚基的PEF结构域共表达。 如预测的那样，钙蛋白酶1的PEF结构域异二聚化，钙蛋白酶3的PEF结构域形成同源二聚体。 消化道特异性钙蛋白酶9的PEF结构域与小亚基异二聚化，以及钙蛋白酶13的PEF结构域，在肺和睾丸中普遍存在，主要被发现为具有少量异二聚体的同二聚体。 这些结果表明，是否重组生产一个特定的钙蛋白酶需要共表达的小亚基，以及是否这种钙蛋白酶可能是活跃的小亚基敲除小鼠。此外，由于内源性抑制剂钙蛋白酶抑制剂结合到大小亚基上的PEF结构域，因此具有两个活性位点的同型二聚体钙蛋白酶3和13不太可能结合钙蛋白酶抑制剂或被钙蛋白酶抑制剂沉默。
The two main mammalian calpains, 1 and 2, are heterodimers of a large 80 kDa and a small 28 kDa subunit that together bind multiple calcium ions during enzyme activation. The main contact between the two subunits of these intracellular cysteine proteases is through a pairing of the fifth EF‐hand of their C‐terminal penta‐EF‐hand (PEF) domains. From modeling studies and observation of crystal structures, it is not obvious why these calpains form heterodimers with the small subunit rather than homodimers of the large subunit, as suggested for calpain 3 (p94). Therefore, we have used a differential tagging system to determine which of the other PEF domain‐containing calpains form heterodimers and which form homodimers. His6‐tagged PEF domains of calpains 1, 3, 9 and 13 were coexpressed with the PEF domain of the small subunit that had been tagged with an antifreeze protein. As predicted, the PEF domain of calpain 1 heterodimerized and that of calpain 3 formed a homodimer. The PEF domain of digestive tract‐specific calpain 9 heterodimerized with the small subunit, and that of calpain 13, prevalent in lung and testis, was mainly found as a homodimer with a small amount of heterodimer. These results indicate whether recombinant production of a particular calpain requires coexpression of the small subunit, and whether this calpain is likely to be active in a small subunit knockout mouse. Furthermore, as the endogenous inhibitor calpastatin binds to PEF domains on the large and small subunit, it is less likely that the homodimeric calpains 3 and 13 with two active sites will bind or be silenced by calpastatin.
钙蛋白酶抑制蛋白抑制钙蛋白酶的结构模型：钙蛋白酶天然结构域VI及其与钙蛋白酶肽和小分子抑制剂的复合物的晶体结构。
影响因子：
5.6
作者：
Todd,Bice;Moore,Dwight;Deivanayagam,ChampionCS;Lin,Guang-da;Chattopadhyay,Debasish;Maki,Masatoshi;Wang,KevinKW;Narayana,SthanamVL
通讯作者：
Narayana,SthanamVL