Grb2 binds CD28

CD28 binds to several signaling proteins, including Grb2, through its Src homology domains. The phosphorylated YMNM motif in CD28's cytoplasmic tail primarily interacts with Grb2's SH2 domain, while the SH3 domain of Grb2 simultaneously engages a diproline motif in the C-terminal region of CD28. This dual binding mechanism enhances the stability of the CD28-Grb2 interaction, facilitating downstream signaling events that are crucial for T cell activation and cytokine production (Okkenhaug and Rottapel 1998).

CD28通过其Src同源结构域与多种信号蛋白结合，包括Grb2。CD28胞浆尾部的磷酸化YMNM基序主要与Grb2的SH2结构域相互作用，同时，Grb2的SH3结构域亦与CD28的C端区域的二丙氨酸基序形成交联。这种双重结合机制增强了CD28-Grb2相互作用的稳定性，从而促进T细胞活化和细胞因子产生的下游信号传导事件（Okkenhaug and Rottapel 1998）。