Molecular Mechanisms of podosome formation

绝大多数癌症发生在上皮组织，产生癌。鉴于上皮细胞位于基底膜下方，它们必须将基底膜降解，才能到达较远的部位。为了启动侵袭过程，它们必须与细胞外基质（ECM）接触。因此，细胞与基质的相互作用一定是癌细胞入侵的触发因素之一。为了渗透到ECM中，富含肌动蛋白的附着结构（称为侵足体或足质体）被认为在降解ECM中起着关键作用。我研究了src转化的NIH3T3细胞侵入样体/足质体形成的机制。在本研究中，我基于RNAi的结果，结合质谱鉴定结合蛋白，蛋白相互作用和活细胞成像分析，建立了侵入adopodium形成的阶梯机制。由于蛋白磷酸化状态的改变和质膜上磷酸肌苷组成的改变，侵殖虫从局灶黏附（FAs）开始。肌动蛋白聚合的开始是由PI(3,4)P2的产生和Tks5的募集引发的，随后是N-WASP的积累。这一步骤涉及Tks5与PI(3,4)P2和Grb2在FAs的复杂相互作用

The great majority of cancers occur in epithelial tissues, yielding carcinomas. Given that epithelial cells are on the basement membrane underneath, they must degrade it to travel to distant sites. To initiate the invasion process, they must make contact with the extracellular matrices (ECM). Thus, the cell-matrix interactions must be one of the triggers that allow cancer cells to invade. To penetrate into the ECM, actin-rich adhesion structures called invadopodia or podosomes is thought to play pivotal roles for degrading it. I have studied the mechanism of invadopodium/podosome formation in Src-transformed NIH3T3 cells. In this study, based on the results of RNAi, identification of binding proteins by mass spectrometry, protein interaction and live-cell imaging analysis, I have established a stepwise mechanism for invadopodium formation. Invadopodia initiate from focal adhesions (FAs) due to changes in the phosphorylation status of proteins and in the composition of phosphoinositides on the plasma membrane. The onset of actin polymerization is triggered by PI(3,4)P2 production and Tks5 recruitment followed by N-WASP accumulation. This step involves intricate interactions of Tks5 with both PI(3,4)P2 and Grb2 at FAs