Lactococcus lactis: Recent developments in functional expression of membrane proteins

Abstract

Membrane proteins (MPs) play key roles in most important cellular processes ranging from cell-to-cell communication to signaling processes. Despite recent improvements, the expression of functionally folded MPs in sufficient amounts for functional and structural characterization remains a challenge. Indeed, it is still difficult to predict whether a protein can be overproduced in a functional state in some expression system(s), although studies of high-throughput screens have been issued in recent years. Prokaryotic expression systems present several advantages over eukaryotic ones. Among them, Lactococcus lactis (L. lactis) has emerged in the past years as a good alternative expression system toEscherichia coli. The purpose of this chapter is to describeL. lactis and its tightly inducible system, nisin-controlled gene expression (NICE), for the expression of MPs from both prokaryotic and eukaryotic origins. Moreover, we will describe the functional characterization of some MPs produced in L. lactis.