Activating and deactivating mutations in the receptor interaction site of GDF5 cause symphalangism or brachydactyly type A2
Activating and deactivating mutations in the receptor interaction site of GDF5 cause symphalangism or brachydactyly type A2
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DOI：
10.1172/jci25118
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发表时间：
2005-09-01
影响因子：
15.9
通讯作者：
Mundlos, S
中科院分区：
文献类型：
--
作者：
Seemann, P;Schwappacher, R;Mundlos, S
在这里，我们描述了生长和分化因子 5 (GDF5) 中的 2 个突变，它们改变了受体结合亲和力。它们会导致 A2 型短指畸形 (L441P) 和并指畸形 (R438L)，这两种疾病先前分别与 GDF5 受体骨形态发生蛋白受体 1b 型 (BMPR1B) 和 BMP 拮抗剂 NOGGIN 的突变相关。我们在肢芽微团培养物中表达突变蛋白，并用重组 GDF5 处理 ATDC5 和 C2C12 细胞。我们的结果表明 L441P 突变体几乎没有活性。相反，与WT GDF5相比，R438L突变体显示出增加的生物活性。生物传感器相互作用分析显示，L441P 突变体与 BMPR1A 和 BMPR1B 胞外域的结合丧失，而 R438L 突变体与 BMPR1B 的结合正常，但与 BMPR1A（通常由 BMP2 激活的受体）的结合增加。两种突变体与 NOGGIN 的结合都是正常的。因此，短指型 A2 表型 (L441P) 是由配体-受体相互作用的抑制引起的，而共指表型 (R438L) 是由受体结合特异性的丧失引起的，从而通过获得 BMP2 样特性而获得功能。所提出的实验已经确定了体内 GDF5 受体结合特异性的一些主要决定因素，并为生成 GDF5 拮抗剂和超级激动剂开辟了新的前景。
Here we describe 2 mutations in growth and differentiation factor 5 (GDF5) that alter receptor-binding affinities. They cause brachydactyly type A2 (L441P) and symphalangism (R438L), conditions previously associated with mutations in the GDF5 receptor bone morphogenetic protein receptor type 1b (BMPR1B) and the BMP antagonist NOGGIN, respectively. We expressed the mutant proteins in limb bud micromass culture and treated ATDC5 and C2C12 cells with recombinant GDF5. Our results indicated that the L441P mutant is almost inactive. The R438L mutant, in contrast, showed increased biological activity when compared with WT GDF5. Biosensor interaction analyses revealed loss of binding to BMPR1A and BMPR1B ectodomains for the L441P mutant, whereas the R438L mutant showed normal binding to BMPR1B but increased binding to BMPR1A, the receptor normally activated by BMP2. The binding to NOGGIN was normal for both mutants. Thus, the brachydactyly type A2 phenotype (L441P) is caused by inhibition of the ligand-receptor interaction, whereas the symphalangism phenotype (R438L) is caused by a loss of receptor-binding specificity, resulting in a gain of function by the acquisition of BMP2-like properties. The presented experiments have identified some of the main determinants of GDF5 receptor-binding specificity in vivo and open new prospects for generating antagonists and superagonists of GDF5.