JQ-1 is a triazolothienodiazepine compound that inhibits the BET bromodomain (BRD) family of proteins. Although it is a diazepine-like compound, JQ-1 exhibits no sedative or anxiolytic efficacy. JQ-1 was initially in development as a non-hormonal male contraceptive, inhibiting bromodomain testis-specific protein BRDT and chromatin remodeling during spermatogenesis, therefore preventing sperm production. This compound also activates latent HIV-1 in vitro and inhibits T cell proliferation through downregulation of T cell activation signals CD3, CD28, and CXCR4; JQ-1 is currently used as an experimental tool for examining mechanisms of HIV-1 latency. Additionally, JQ-1 exhibits anticancer chemotherapeutic activity in vitro and in vivo; through its inhibition of BRD4, JQ-1 suppresses Myc expression, IL-7R expression, and reduces JAK/STAT phosphorylation, inducing cell cycle arrest and altering survival in a variety of cell lines. Biological bromodomain binding activity comes primarily from (+)-JQ-1; the (-)-JQ-1 stereoisomer does not bind BET bromodomains.