i3S-Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135 Porto, Portugal.
IBMC, Instituto de Biologia Celular e Molecular, 4200-135 Porto, Portugal.
Cells. 2023 Jul 17;12(14):1871. doi: 10.3390/cells12141871.
Non-muscle myosin 2A (NM2A) is a key cytoskeletal enzyme that, along with actin, assembles into actomyosin filaments inside cells. NM2A is fundamental for cell adhesion and motility, playing important functions in different stages of development and during the progression of viral and bacterial infections. Phosphorylation events regulate the activity and the cellular localization of NM2A. We previously identified the tyrosine phosphorylation of residue 158 (pTyr) in the motor domain of the NM2A heavy chain. This phosphorylation can be promoted by infection of epithelial cells and is dependent on Src kinase; however, its molecular role is unknown. Here, we show that the status of pTyr defines cytoskeletal organization, affects the assembly/disassembly of focal adhesions, and interferes with cell migration. Cells overexpressing a non-phosphorylatable NM2A variant or expressing reduced levels of Src kinase display increased stress fibers and larger focal adhesions, suggesting an altered contraction status consistent with the increased NM2A activity that we also observed. We propose NM2A pTyr as a novel layer of regulation of actomyosin cytoskeleton organization.
非肌肉肌球蛋白 2A（NM2A）是一种关键的细胞骨架酶，与肌动蛋白一起在细胞内组装成肌球蛋白细丝。NM2A 对细胞黏附性和运动性至关重要，在不同的发育阶段和病毒及细菌感染的进展过程中发挥着重要作用。磷酸化事件调节 NM2A 的活性和细胞定位。我们之前发现 NM2A 重链马达结构域残基 158 的酪氨酸磷酸化（pTyr）。这种磷酸化可以被 感染上皮细胞所促进，并且依赖于Src 激酶；然而，其分子作用尚不清楚。在这里，我们表明 pTyr 的状态决定了细胞骨架的组织，影响了焦点黏附的组装/拆卸，并干扰了细胞迁移。过表达非磷酸化 NM2A 变体的细胞或表达降低水平的 Src 激酶显示出增加的应激纤维和更大的焦点黏附，这表明与我们也观察到的 NM2A 活性增加一致的收缩状态发生改变。我们提出 NM2A pTyr 作为肌动球蛋白细胞骨架组织调节的新层次。
