da Silva Luiz E, Paim Lia M G, Lyalina Tatiana, Menezes Ana P J, da Cunha Julia P C, Bechstedt Susanne, Cella Nathalie
Department of Cell and Developmental Biology, University of São Paulo, São Paulo, Brazil.
Department of Anatomy and Cell Biology, McGill University, Montreal, Canada.
Commun Biol. 2025 Aug 22;8(1):1262. doi: 10.1038/s42003-025-08688-3.
Maspin/SerpinB5 is an abundant and pleiotropic protein mostly expressed by epithelia. Initially described as a tumor suppressor, it has been reported as a regulator of cell adhesion, migration, and invasion. How intracellular Maspin orchestrates these processes is poorly understood. In this study, we utilized Affinity purification-Mass spectrometry (AP/MS) alongside in vitro reconstitution assays to establish that Maspin directly interacts with microtubules and microfilaments. Additionally, CRISPR/Cas9-mediated GFP tagging of endogenous Maspin, combined with immunostaining, revealed its localization at the cortical cytoskeleton and the mitotic spindle. Depletion of Maspin by RNAi and CRISPR/Cas9 in non-transformed epithelial cell lines modifies cell-cell contact and promotes cytoskeletal rearrangements. Concomitantly, we observed a modest upregulation of mesenchymal markers during interphase and abnormal cell rounding during mitosis. An evaluation of Maspin's effect on microtubules revealed that it suppresses their growth in vitro and in cells. Collectively, these results demonstrate that Maspin acts dynamically at the interface of the cytoskeleton and adhesion sites, modulating cell shape.
Maspin/丝氨酸蛋白酶抑制剂B5是一种主要由上皮细胞表达的丰富且具有多效性的蛋白质。最初被描述为一种肿瘤抑制因子,后来有报道称它是细胞黏附、迁移和侵袭的调节因子。细胞内的Maspin如何协调这些过程尚不清楚。在本研究中,我们利用亲和纯化-质谱分析(AP/MS)以及体外重组实验,确定Maspin直接与微管和微丝相互作用。此外,通过CRISPR/Cas9对内源性Maspin进行绿色荧光蛋白标记,并结合免疫染色,揭示了其在皮质细胞骨架和有丝分裂纺锤体上的定位。在未转化的上皮细胞系中,通过RNA干扰和CRISPR/Cas9去除Maspin会改变细胞间接触并促进细胞骨架重排。同时,我们观察到在间期间充质标志物有适度上调,在有丝分裂期间细胞出现异常变圆。对Maspin对微管的影响进行评估发现,它在体外和细胞内均抑制微管生长。总的来说,这些结果表明Maspin在细胞骨架和黏附位点的界面动态发挥作用,调节细胞形状。