Kawasugi K, French P W, Penny R, Ludowyke R I
Centre for Immunology, St. Vincent's Hospital, Sydney, Australia.
Cell Motil Cytoskeleton. 1995;31(3):215-24. doi: 10.1002/cm.970310305.
Adherence of cells to the extracellular matrix via focal adhesions is known to modulate many cellular functions. However, the role of focal adhesions in the regulation of secretion is unclear. To examine this we have used the RBL-2H3 rat mast cell line, in which we and others have observed cytoskeletal rearrangements and increased cell spreading during secretion. All activators of secretion examined, whether acting specifically through or bypassing the IgE-receptor, induced the assembly of focal adhesions, as defined by the localization of vinculin and talin. The extent of focal adhesion formation correlated with the extent of secretion and the time course of secretion also correlated with that of the assembly of focal adhesions. To examine the mechanism by which focal adhesion formation occurred, the protein kinase C inhibitor bisindolylmaleimide was used. Bisindolylmaleimide caused complete inhibition of both secretion and focal adhesion formation induced by antigen or the calcium ionophore A23187. Although PMA did not induce secretion, it induced focal adhesion assembly which was inhibited by bisindolylmaleimide. The inhibitor had no effect on secretion or focal adhesion formation induced by the ATP analogue, ATP gamma S in permeabilized cells, indicating ATP gamma S acts after the activation of protein kinase C in the secretory pathway. These data provide novel evidence that the formation of focal adhesions may have a role in the process of secretion from mast cells.
已知细胞通过黏着斑与细胞外基质的黏附可调节多种细胞功能。然而，黏着斑在分泌调节中的作用尚不清楚。为了研究这一点，我们使用了RBL-2H3大鼠肥大细胞系，在该细胞系中我们和其他人观察到在分泌过程中细胞骨架重排和细胞铺展增加。所检测的所有分泌激活剂，无论其是通过IgE受体特异性作用还是绕过IgE受体，均诱导了黏着斑的组装，这可通过纽蛋白和踝蛋白的定位来定义。黏着斑形成的程度与分泌程度相关，分泌的时间进程也与黏着斑组装的时间进程相关。为了研究黏着斑形成的机制，使用了蛋白激酶C抑制剂双吲哚马来酰亚胺。双吲哚马来酰亚胺完全抑制了由抗原或钙离子载体A23187诱导的分泌和黏着斑形成。尽管佛波酯不诱导分泌，但它诱导了黏着斑组装，而这被双吲哚马来酰亚胺抑制。该抑制剂对通透细胞中由ATP类似物ATPγS诱导的分泌或黏着斑形成没有影响，表明ATPγS在分泌途径中蛋白激酶C激活后起作用。这些数据提供了新的证据，表明黏着斑的形成可能在肥大细胞的分泌过程中起作用。
