The present invention relates to 11cby, in particular 11cby polypeptides and 11cby polynucleotides, recombinant materials and methods for their production. In another aspect, the invention relates to methods for using such polypeptides and polynucleotides, including the treatment of bacterial, fungal, protozoan and viral infections, particularly infection caused by HIV-1 or HIV-2; pain; cancers; diabetes; obesity; feeding and drinking abnormalities, such as anorexia and bulimia; asthma; Parkinson's disease; both acute and congestive heart failure; hypotension; hypertension; urinary retention; osteoporosis; angina pectoris; myocardial infarction; ulcers; allergies; benign prostatic hypertrophy and psychotic and neurological disorders, including anxiety, schizophrenia, manic depression, delirium, dementia or severe mental retardation, and dyskinesias, such as Huntington's disease or Gilles dela Tourett's syndrome, hereinafter referred to as "the Diseases", among others. In a still further aspect, the invention relates to diagnostic and prognostic assays for detecting diseases associated with inappropriate 11cby activity or levels. A method of performing genetic association studies for searching a disease susceptibility and/or drug response genes comprising using polymorphic markers in 11cby polynucleotides.