The GLIPR1 family consists of three core members， designated GLIPR1， GLIPR1L1 (GLIPR1-like protein 1) and GLIPR1L2， which form a distinct subgroup within the cysteine-rich secretory protein (CRISP)， antigen 5 and pathogenesis-related 1 (CAP) superfamily. Each member of the CAP superfamily has a conserved N-terminal CAP domain and a distinct C-terminal extension. CAP superfamily proteins are hypothesized to have roles in immunity， cell adhesion， carcinogenesis and male fertility. GLIPR1L1 is a 242 amino acid secreted protein. Highly expressed in testis， GLIPR1L1 exists as two isoforms produced by alternative splicing events. GLIPR1L1 is encoded by a gene that maps to human chromosome 12q21.1 and mouse chromosome 10 D2.