MxiM, a Shigella pilot protein, is essential for the assembly and membrane association of the Shigella secretin MxiD. MxiM contains an orthologous secretin component and has a specific binding domain for the acyl chains of bacterial lipids [1]. The C terminal domain of MxiD hinders lipid binding to MxiM [1].

1: Structure and biochemical analysis of a secretin pilot protein. Lario PI, Pfuetzner RA, Frey EA, Creagh L, Haynes C, Maurelli AT, Strynadka NC; EMBO J. 2005;24:1111-1121. PMID:15775974