Introduction:

Receptor Activity Modifying Proteins, or RAMPs, are small proteins which serve to modulate the activity of several G protein-coupled receptors (GPCRs).

These RAMP-GPCR interactions can result in a variety of actions, including the heterodimerization of novel receptor phenotypes, and the chaperoning of the receptor to the cell surface.

The novel receptor phenotypes, and consequently the ligand binding, is ultimately determined by the isoform of RAMP interaction with the given GPCR. As an example, the interactions between RAMPs 1-3 and the calcitonin-like receptor is shown.

Phenotype of RAMP + CLR complex is determined by RAMP isoform

Significance:

Originally, the interaction between RAMPs and GPCRs was thought to be limited to the B-class GPCRs, which consists of receptors which interact with peptide hormones, such as glucagon, secretin and calcitonin.

Since then, experimental findings have shown atleast one C-class GPCR to also be be regulated by RAMPs.

The research into RAMPs has also opened the field to the identification of RAMP-like proteins - two of which are receptor-transporting proteins (RTPs) and receptor expression enhancing proteins (REEPS). These function similarly to RAMPs, particularly with odorant GPCRs.

As the various interactions of RAMPs continues to expand, there will be a growing need for a central repository to explore and predict these interactions. RampDB aims to serve as that central repository.

Transporting of CaSR, a C-class GPCR, to the cell surface by RAMPs 1 or 3