FKBP5 and psychiatric disorder: For example, there are two genes well-established to be involved in the regulation of stress response, including the glucocorticoid receptor chaperone protein gene FK506 Binding protein 5 (FKBP5), which is an important regulator of glucocorticoid receptor sensitivity (30, 31) and the serotonin transporter gene (SLC6A4), which has been implicated in stress response and increased risk for psychiatric disorders (32).