Fos-related antigen 1 (FOSL1) is a protein that in humans is encoded by the FOSL1 gene. 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.The synthetic peptide used to raise the antibody Cat. No. 251523 is selected from a sequence within the center region of human FOSL1. For blocking experiments, a 10 to 100 fold molar excess to antibody is recommended.