fos基因家族由4个成员组成：fos、fosb、fosl1和fosl2。这些基因编码亮氨酸拉链蛋白，可与Jun家族的蛋白质二聚，从而形成转录因子复合物AP-1。因此，fos蛋白被认为是细胞增殖、分化和转化的调节因子。在某些情况下，fos基因的表达也与凋亡细胞死亡有关。
The Fos gene family consists of 4 members: FOS, FOSB, FOSL1, and FOSL2. These genes encode leucine zipper proteins that can dimerize with proteins of the JUN family, thereby forming the transcription factor complex AP-1. As such, the FOS proteins have been implicated as regulators of cell proliferation, differentiation, and transformation. In some cases, expression of the FOS gene has also been associated with apoptotic cell death.