Polypeptide Substrate Accessibility Hypothesis: Gain-of-Function R206H Mutation Allosterically Affects Activin Receptor-like Protein Kinase Activity.
Polypeptide Substrate Accessibility Hypothesis: Gain-of-Function R206H Mutation Allosterically Affects Activin Receptor-like Protein Kinase Activity.
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DOI：
10.3390/biom13071129
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发表时间：
2023-07-14
期刊：
影响因子：
5.5
通讯作者：
中科院分区：
文献类型：
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尽管在结构上与 II 型对应物类似，但 I 型或激活素受体样激酶 (ALK) 被蛋白激酶结构域之前的亚稳态螺旋-环-螺旋 (HLH) 元件分开，根据长期存在的范例，该元件作为抑制剂与底物结合开关发挥着被动但关键的作用。直接邻近组成性激活取代位置的倒数第二个残基的密码子中的单个复发突变会导致 ACVR1/ALK2 较温和的激活，从而导致进行性骨化性纤维发育不良 (FOP) 患者的散发性异位骨沉积。为了确定获得功能的蛋白质结构-功能基础，通过体外激酶和蛋白质-蛋白质相互作用分析，将 R206H 突变体、Q207D（天冬氨酸取代的 caALK2）和 HLH 亚结构域截短 (208 Ntrunc) 形式与野生型酶进行比较，并通过原代小鼠中的信号读出 (p-Smad) 进行补充 胚胎成纤维细胞和果蝇S2细胞。与范例相反，即使在不存在 FKBP12 的情况下，HLH 子结构域也会主动抑制该酶的磷酸转移酶活性。出乎意料的是，扰动 HLH 子结构域会在远处（即变构地）升高 ATP 结合和多肽相互作用活性位点裂缝处的激酶活性。由于异六聚体细胞质信号复合物内 I 型活性位点的构象发生变构改变（由激活素 II 型受体在细胞外组装），对多肽底物（BMP Smad C 末端尾部）的可及性被推测会产生负责间歇性异位骨化的 R206H 突变蛋白的功能增益。 FOP。
Although structurally similar to type II counterparts, type I or activin receptor-like kinases (ALKs) are set apart by a metastable helix–loop–helix (HLH) element preceding the protein kinase domain that, according to a longstanding paradigm, serves passive albeit critical roles as an inhibitor-to-substrate-binding switch. A single recurrent mutation in the codon of the penultimate residue, directly adjacent the position of a constitutively activating substitution, causes milder activation of ACVR1/ALK2 leading to sporadic heterotopic bone deposition in patients presenting with fibrodysplasia ossificans progressiva, or FOP. To determine the protein structural–functional basis for the gain of function, R206H mutant, Q207D (aspartate-substituted caALK2) and HLH subdomain-truncated (208 Ntrunc) forms were compared to one another and the wild-type enzyme through in vitro kinase and protein–protein interaction analyses that were complemented by signaling read-out (p-Smad) in primary mouse embryonic fibroblasts and Drosophila S2 cells. Contrary to the paradigm, the HLH subdomain actively suppressed the phosphotransferase activity of the enzyme, even in the absence of FKBP12. Unexpectedly, perturbation of the HLH subdomain elevated kinase activity at a distance, i.e., allosterically, at the ATP-binding and polypeptide-interacting active site cleft. Accessibility to polypeptide substrate (BMP Smad C-terminal tails) due to allosterically altered conformations of type I active sites within heterohexameric cytoplasmic signaling complexes—assembled noncanonically by activin-type II receptors extracellularly—is hypothesized to produce a gain of function of the R206H mutant protein responsible for episodic heterotopic ossification in FOP.
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影响因子：
14.8
作者：
Kozakov D;Hall DR;Xia B;Porter KA;Padhorny D;Yueh C;Beglov D;Vajda S
通讯作者：
Vajda S
DOI：
10.1073/pnas.2213090120
发表时间：
2023-02-21
影响因子：
11.1
作者：
通讯作者：
--
影响因子：
2.5
作者：
Le, Viet Q.;Wharton, Kristi A.
通讯作者：
Wharton, Kristi A.
影响因子：
4.8
作者：
Nohe, A;Hassel, S;Knaus, P
通讯作者：
Knaus, P
影响因子：
16.6
作者：
Agnew C;Ayaz P;Kashima R;Loving HS;Ghatpande P;Kung JE;Underbakke ES;Shan Y;Shaw DE;Hata A;Jura N
通讯作者：
Jura N