Figure 8. A unifying model proposing a conserved role for CREB3 proteins in responding to potentially diverse signals, leading to increased secretory capacity and cargo secretion.

With regard to secretory functions, responses promoted by CREB3 proteins can be either general and controlled by all CREB3 members, e.g., regulating general flux or supplying limiting factors or be specific for different CREB3 members e.g., increasing distinct limited secretory components required for distinct types of cargos or in different cells. Similarly, apart from genes for secretory components, CREB3 proteins can regulate other targets such as the cargos themselves and again these could be common or distinct. In the response output (top right of diagram), common responses promoted by all family members are indicated by the single blue outline, with responses promoted by individual members superimposed in smaller brown squares. Whereas to date most CREB3 target gene encode either secretory pathway components, secreted cargos or modifying enzymes, additional classes of targets catering to distinct stimuli are likely to also be regulated by CREB3 associated pathways.