信号转导接头蛋白或信号转导衔接蛋白（英语：Signal transducing adaptor proteins）是信号转导通路中的重要蛋白质。接头蛋白上有着各种能与其它蛋白结合的结构域，能形成各种信号复合体。这些蛋白质往往本身缺乏酶的活性，而是通过特异性的蛋白-蛋白交互作用形成蛋白质复合体来激活下游信号通路。常见的接头蛋白有MyD88、Grb2和SHC1等。

Signal transducing adaptor proteins are proteins that are accessory to main proteins in a signal transduction pathway. Adaptor proteins contain a variety of protein-binding modules that link protein-binding partners together and facilitate the creation of larger signaling complexes. These proteins tend to lack any intrinsic enzymatic activity themselves but instead mediate specific protein–protein interactions that drive the formation of protein complexes. Examples of adaptor proteins include MyD88, Grb2 and SHC1.