Protein Domain

PDZ

The PDZ domain is a common structural domain of 80-90 amino-acids found in the signaling proteins of all three kingdoms of life. PDZ is an acronym combining the first letters of three proteins — post synaptic density protein (PSD95), Drosophila disc large tumor suppressor (Dlg1), and zonula occludens-1 protein (zo-1) — which were first discovered to share the domain. It has previously been referred to as DHR (Dlg homologous region) or GLGF (glycine-leucine-glycine-phenylalanine) domains.

Proteins with these domains help hold together and organize signaling complexes at cellular membranes. In general PDZ domains bind to a short region of the C-terminus of other specific proteins. These short regions bind to the PDZ domain by beta sheet augmentation. This means that the beta sheet in the PDZ domain is extended by the addition of a further beta strand from the tail of the binding partner protein.

FERM

FERM domain (F for 4.1 protein, E for ezrin, R for radixin and M for moesin) is a widespread protein module involved in localising proteins to the plasma membrane. FERM domains are found in a number of cytoskeletal-associated proteins that associate with various proteins at the interface between the plasma membrane and the cytoskeleton. The FERM domain is located at the N terminus in the majority of proteins in which it is found.