Froger Alexandrine, Rolland Jean-Paul, Bron Patrick, Lagrée Valérie, Cahérec Françoise Le, Deschamps Stéphane, Hubert Jean-François, Pellerin Isabelle, Thomas Daniel, Delamarche Christian
UMR CNRS, Interactions Cellulaires et Moléculaires, Equipe Canaux et Récepteurs Membranaires, Université de Rennes 1, Campus de Beaulieu, 35042 Rennes cedex, France1.
Microbiology (Reading). 2001 May;147(Pt 5):1129-1135. doi: 10.1099/00221287-147-5-1129.
The major intrinsic proteins (MIPs) constitute a widespread membrane channel family essential for osmotic cell equilibrium. The MIPs can be classified into three functional subgroups: aquaporins, glycerol facilitators and aquaglyceroporins. Bacterial MIP genes have been identified in archaea as well as in Gram-positive and Gram-negative eubacteria. However, with the exception of Escherichia coli, most bacterial MIPs have been analysed by sequence homology. Since no MIP has yet been functionally characterized in Gram-positive bacteria, we have studied one of these members from Lactococcus lactis. This MIP is shown to be permeable to glycerol, like E. coli GlpF, and to water, like E. coli AqpZ. This is the first characterization of a microbial MIP that has a mixed function. This result provides important insights to reconstruct the evolutionary history of the MIP family and to elucidate the molecular pathway of water and other solutes in these channels.
主要内在蛋白（MIPs）构成了一个广泛存在的膜通道家族，对细胞渗透平衡至关重要。MIPs可分为三个功能亚组：水通道蛋白、甘油转运蛋白和水甘油通道蛋白。在古细菌以及革兰氏阳性和革兰氏阴性真细菌中都已鉴定出细菌MIP基因。然而，除了大肠杆菌外，大多数细菌MIPs都是通过序列同源性进行分析的。由于革兰氏阳性细菌中尚未对任何MIP进行功能表征，我们研究了乳酸乳球菌中的一个此类成员。结果表明，该MIP像大肠杆菌GlpF一样对甘油具有通透性，像大肠杆菌AqpZ一样对水具有通透性。这是对具有混合功能的微生物MIP的首次表征。这一结果为重建MIP家族的进化史以及阐明这些通道中水和其他溶质的分子途径提供了重要见解。
