集成素（英语：Integrin，又译为整联蛋白）是一种介导细胞和其外环境（如细胞外基质，ECM）之间的连接的跨膜受体。在信号转导中，集成素将ECM的化学成分与力学状态等有关信息传入细胞。 因此，集成素除了穿过膜的机械作用，也参与了细胞消息、细胞周期之调节、细胞型态以及细胞的运动。

通常，受体的作用是将外环境的变化通知细胞并引起细胞反应。但集成素不仅介导由外到内的信号，也介导由内到外的细胞信号。因此集成素不但将ECM的信息传递给细胞，也将细胞的状态表达给外界，从而可以迅速和灵活地响应环境中的变化，比如血液的凝固作用。

Integrins are transmembrane receptors that are the bridges for cell-cell and cell-extracellular matrix (ECM) interactions. When triggered, integrins in turn trigger chemical pathways to the interior (signal transduction), such as the chemical composition and mechanical status of the ECM, which results in a response (activation of transcription) such as regulation of the cell cycle, cell shape, and/or motility; or new receptors being added to the cell membrane. This allows rapid and flexible responses to events at the cell surface, for example to signal platelets to initiate an interaction with coagulation factors.