A Mutation in the Extracellular Cysteine-Rich Repeat Region of the β3 Subunit Activates Integrins IIbβ3 and Vβ3
A Mutation in the Extracellular Cysteine-Rich Repeat Region of the β3 Subunit Activates Integrins IIbβ3 and Vβ3
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β3 亚基胞外富含半胱氨酸重复区域的突变激活整合素 IIbβ3 和 Vβ3
DOI：
10.1182/blood.v93.8.2559
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发表时间：
1999
期刊：
影响因子：
20.3
通讯作者：
S. Shattil
中科院分区：
文献类型：
--
作者：
H. Kashiwagi;Y. Tomiyama;S. Tadokoro;S. Honda;M. Shiraga;H. Mizutani;M. Handa;Y. Kurata;Y. Matsuzawa;S. Shattil
由内而外的信号传导通过受体亲和力和/或亲和力的变化来调节整合素的配体结合功能。例如，IIbβ3 在静息血小板中处于低亲和力/亲和力状态，血小板激动剂激活受体使纤维蛋白原能够结合。此外，整合素胞质尾部的某些突变和截短与高亲和力/亲合力受体相关。为了进一步评估整合素激活的结构基础，筛选了稳定的中国仓鼠卵巢 (CHO) 细胞转染子中的 IIbβ3 的高亲和力/亲和力变体。一个克隆 (AM-1) 表达组成型活性 IIbβ3，证据如下：(1) 可溶性纤维蛋白原与 PAC1（一种配体模拟抗 IIbβ3 抗体）结合； (2)纤维蛋白原依赖性细胞聚集。 293 细胞中的序列分析和突变体表达证明，β3(T562N) 富含半胱氨酸的胞外部分中的单个氨基酸取代负责受体激活。事实上，T562N 还激活 Vβ3，导致可溶性纤维蛋白原自发结合到 293 细胞。相反，T562A 和 T562Q 均不激活 IIbβ3，表明在残基 562 处获得天冬酰胺是相关变量。 T562N 还导致 β3 的异常糖基化，但这并不是受体激活的原因。可溶性纤维蛋白原与 IIbβ3(T562N) 的结合不足以触发 pp125FAK 的酪氨酸磷酸化，表明在整联蛋白信号转导过程中需要额外的配体结合后事件来激活该蛋白酪氨酸激酶。这些研究在配体结合区和细胞质尾部之间的β3中间区域发现了一种新的功能获得性突变，并且表明该区域参与了由内而外信号传导过程中的整合素结构变化。
Inside-out signaling regulates the ligand-binding function of integrins through changes in receptor affinity and/or avidity. For example, IIbβ3 is in a low-affinity/avidity state in resting platelets, and activation of the receptor by platelet agonists enables fibrinogen to bind. In addition, certain mutations and truncations of the integrin cytoplasmic tails are associated with a high-affinity/avidity receptor. To further evaluate the structural basis of integrin activation, stable Chinese hamster ovary (CHO) cell transfectants were screened for high-affinity/avidity variants of IIbβ3. One clone (AM-1) expressed constitutively active IIbβ3, as evidenced by (1) binding of soluble fibrinogen and PAC1, a ligand-mimetic antiIIbβ3antibody; and (2) fibrinogen-dependent cell aggregation. Sequence analysis and mutant expression in 293 cells proved that a single amino acid substitution in the cysteine-rich, extracellular portion of β3(T562N) was responsible for receptor activation. In fact, T562N also activated Vβ3, leading to spontaneous binding of soluble fibrinogen to 293 cells. In contrast, neither T562A nor T562Q activated IIbβ3, suggesting that acquisition of asparagine at residue 562 was the relevant variable. T562N also led to aberrant glycosylation of β3, but this was not responsible for the receptor activation. The binding of soluble fibrinogen to IIbβ3(T562N) was not sufficient to trigger tyrosine phosphorylation of pp125FAK, indicating that additional post-ligand binding events are required to activate this protein tyrosine kinase during integrin signaling. These studies have uncovered a novel gain-of-function mutation in a region of β3 intermediate between the ligand-binding region and the cytoplasmic tail, and they suggest that this region is involved in integrin structural changes during inside-out signaling.
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对大鼠和小鼠 β 3 整合素 (GPIIIA) 的 cDNA 衍生序列与其人类对应物进行比较分析。
影响因子：
3.1
作者：
Cieutat,AM;Rosa,JP;Letourneur,F;Poncz,M;Rifat,S
通讯作者：
Rifat,S
DOI：
10.1073/pnas.84.18.6471
发表时间：
1987-09-01
影响因子：
11.1
作者：
CHERESH, DA
通讯作者：
CHERESH, DA
影响因子：
15.9
作者：
Loftus, JC;Liddington, RC
通讯作者：
Liddington, RC
血小板糖蛋白 IIb-IIIa（α IIb beta 3 整合素）在异源细胞上赋予纤维蛋白原和激活依赖性聚集。
影响因子：
20.3
作者：
Frojmovic,MM;O'Toole,TE;Plow,EF;Loftus,JC;Ginsberg,MH
通讯作者：
Ginsberg,MH
整合素 α IIb beta 3（血小板糖蛋白 IIb-IIIa）的自发突变有助于确定配体结合位点。
DOI：
--
发表时间：
1992
期刊：
The Journal of biological chemistry
影响因子：
--
作者：
Bajt,ML;Ginsberg,MH;Frelinger3rd,AL;Berndt,MC;Loftus,JC
通讯作者：
Loftus,JC