Metallothionein-3 attenuates the effect of Cu2+ ions on actin filaments
Metallothionein-3 attenuates the effect of Cu2+ ions on actin filaments
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DOI：
10.1016/j.jinorgbio.2023.112157
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发表时间：
2023-02-16
影响因子：
3.9
通讯作者：
Vizcarra，Christina L.
中科院分区：
文献类型：
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作者：
Lakha，Rabina;Hachicho，Carla;Vizcarra，Christina L.
金属硫蛋白3（MT-3）是一种富含半胱氨酸的金属结合蛋白，在哺乳动物中枢神经系统和肾脏中表达。各种报道已经假定MT-3通过促进肌动蛋白丝的组装在调节肌动蛋白细胞骨架中的作用。我们产生了已知金属组合物的纯化的重组小鼠MT-3，其与锌（Zn）、铅（Pb）或铜/锌（Cu/Zn）结合。无论是否有肌动蛋白结合蛋白profilin，这些MT-3形式都没有在体外加速肌动蛋白丝聚合。此外，使用共沉降测定，我们没有观察到锌结合的MT-3与肌动蛋白丝的复合物。Cu 2+离子对自己的诱导快速肌动蛋白聚合，我们归因于丝断裂的效果。加入EGTA或Zn结合的MT-3可逆转Cu 2+的这种作用，表明两种分子均可从肌动蛋白中螯合Cu 2+。总之，我们的数据表明，纯化的重组MT-3不直接结合肌动蛋白，但它确实减弱了铜诱导的肌动蛋白丝的断裂。
Metallothionein 3 (MT-3) is a cysteine-rich metal-binding protein that is expressed in the mammalian central nervous system and kidney. Various reports have posited a role for MT-3 in regulating the actin cytoskeleton by promoting the assembly of actin filaments. We generated purified, recombinant mouse MT-3 of known metal compositions, either with zinc (Zn), lead (Pb), or copper/zinc (Cu/Zn) bound. None of these forms of MT-3 accelerated actin filament polymerizationin vitro, either with or without the actin binding protein profilin. Furthermore, using a co-sedimentation assay, we did not observe Zn-bound MT-3 in complex with actin filaments. Cu2+ions on their own induced rapid actin polymerization, an effect that we attribute to filament fragmentation. This effect of Cu2+is reversed by adding either EGTA or Zn-bound MT-3, indicating that either molecule can chelate Cu2+from actin. Altogether, our data indicate that purified recombinant MT-3 does not directly bind actin but it does attenuate the Cu-induced fragmentation of actin filaments.