The Damer Lab is using the model organism, Dictyostelium discoideum, to study a family of of proteins called copines. We have identified six copine genes in the Dictyostelium genome and have thus far focused our studies on one of these genes, copine A (cpnA).

Copines are a family of highly conserved, ubiquitously expressed, calcium-dependent membrane binding proteins found in a variety of eukaryotic organisms. Multiple copine homologs are found in Paramecium, Dictyostelium, Arabidopsis, C. elegans, mice, and humans. Copines are defined by the unique combination of two N-terminal C2 domains responsible for the protein’s calcium-dependent membrane binding properties, and a protein-binding ‘A domain’, similar to the VWA domain of various extracellular matrix proteins and the extracellular portion of integrins.

Dictyostelium provides an ideal system for studying copine function for several reasons. First, although Dictyostelium lives as a single-celled amoeba, it contains multiple copine genes that are diverse in sequence and may carry out distinct functions. Second, Dictyostelium are highly motile, phagocytic cells, possessing organelles and membrane trafficking pathways similar to mammalian cells. Therefore, Dictyostelium serves as a good model for studying membrane trafficking and a particularly good model for many of the phagocytic cells found in human tissues, in which copines are highly expressed. Third, Dictyostelium executes a simple 24-hour developmental program to form multicellular fruiting bodies and thus, Dictyostelium provides a simplistic model to study copine function in cell differentiation, programmed cell death, and development.