The present invention relates to a novel BAIT protein which is a member of serpin superfamily which is expressed primarily in brain tissue. In particular, isolated nucleic acid molecules are provided encoding the human BAIT protein. BAIT polypeptides are also provided as are vectors, host cells and recombinant methods for producing the same. The invention further relates to screening methods for identifying agonists and antagonists of BAIT activity. Also provided are diagnostic methods for detecting nervous system-related disorders and therapeutic methods for treating nervous system-related disorders.