Connecting Cytoskeletal changes in B lymphocytes upon antigen exposure: a critical role for the Src-family kinase Lyn.

真核细胞呈现不同的形状以响应环境刺激。这些变化反映了细胞骨架的改变，对发育、分化和功能是必不可少的。最近的研究已经详细描述了淋巴细胞形状的组织变化，以响应其环境的变化，特别是暴露于抗原。B和T淋巴细胞在其抗原受体（B细胞中的BCR，T细胞中的TCR）接合后重组其细胞骨架。肌动蛋白细胞骨架中抗原驱动的变化由Rho家族GTP酶调节（1），而ezrin/radixin/moesin（ERM）蛋白家族成员将完整的膜蛋白连接到细胞骨架上，并且对于组织抗原-淋巴细胞突触至关重要（2）。根据已发表的数据和初步结果，我们认为BCR相关的酪氨酸激酶林恩在响应抗原将信息从B细胞表面传递到细胞骨架中发挥着至关重要的作用，影响细胞的伸展、收缩和迁移，从而决定B细胞的命运并影响免疫反应的结果。B细胞在响应拴系抗原的扩散和收缩中需要林恩，这意味着林恩-/- B细胞暴露于这些抗原代表了具有关键生物学功能的细胞内异常细胞骨架重排的可再现的、可诱导的和易处理的模型。

ukaryotic cells assume different shapes in response to environmental stimuli. Such changes, reflect-ing alterations in the cytoskeleton of the cell, are essential for development, differentiation and func-tion. Recent studies have detailed the organised changes in the shape of lymphocytes in response to changes in their environment, particularly exposure to antigen. B and T lymphocytes reorganise their cytoskeleton following engagement of their antigen receptors (BCR in B cells, TCR in T cells). Anti-gen-driven changes in the actin cytoskeleton are regulated by Rho-family GTPases (1) while members of the ezrin/radixin/moesin (ERM) family of proteins link integral membrane proteins to the cytoskele-ton and are crucial for organizing the antigen-lymphocyte synapse (2). On the basis of published data and preliminary results, we propose that the BCR-associated tyrosine kinase Lyn plays an essential role in the transmission of information from the B cell surface to the cytoskeleton in response to anti-gen, effecting cell spreading, contraction and migration, thus determining the fate of the B cell and influencing the outcome of the immune response. The requirement for Lyn in B cell spreading and contraction in response to tethered antigen, means that exposure of Lyn-/- B cell to such antigens represents a reproducible, inducible and tractable model of aberrant cytoskeletal rearrangement within cells of a critical biological function.