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EXtracellular Plasmid RESource (EXPRESs) Consortium Icon EXtracellular Plasmid RESource (EXPRESs) Consortium

EXPRESs is a collection of mammalian expression plasmids that encode the extracellular regions of cell surface receptor and secreted proteins as soluble recombinant molecules. The proteins are typically used in systematic protein interaction screens or cellular assays to identify novel interactions or pathways that are important in cellular recognition processes.

Laboratories interested in these approaches have created this resource to facilitate open and free exchange of these expression plasmids. It is hoped that this will encourage other groups to join our community and contribute their own plasmids in the future.


One popular method to detect interactions is AVEXIS (for Avidity-based extracellular interaction screen) in which the extracellular regions of receptor proteins are expressed as both monomeric baits and multimerised enzyme-tagged preys.

Ectodomain inserts:

The inserts that encode the whole ectodomains of cell surface receptors are flanked by two 8 bp cutting enzymes: NotI at the 5' end and AscI at the 3' end. These inserts can then be sub-cloned into a series of expression vectors which have different C-terminal tags. Most vectors are based on the pTT3 plasmid backbone which is described by Durocher et al. Nucleic Acids Research 2002 Jan 15;30(2):E9

A list of commonly-used bait and prey plasmids can be found here:

Plasmid Type Plasmid Name
Bait Cd4d3+4-bio
Prey Cd4d3+4-COMP-b-lac
His-tag Cd4d3+4-6his
Bio-linker-his Cd4d3-bio-linker-6His*
FLAG prey CD200-Cd4d3+4-COMP-blac-3xFLAG-6his
Cd4d3+4-pentamer BasiginCd4d3+4-COMP-his-stop
Type II expression CD69-His-bio
Multi TM expression CD36-bio-His

Plasmid collections exist for:

Laboratories using AVEXIS:


Video showing how AVEXIS works with a detailed protocol description:

Papers showing how AVEXIS can be used: