MlaA is a component of the Mla pathway, an ABC transport system that functions to maintain the asymmetry of the outer membrane [1]. MlaA is required for the intercellular spreading of Shigella flexneri. It is attached to the outer membrane by a lipid anchor [2].

1: An ABC transport system that maintains lipid asymmetry in the gram-negative outer membrane. Malinverni JC, Silhavy TJ; Proc Natl Acad Sci U S A. 2009;106:8009-8014. PMID:19383799

2: Identification and characterization of a chromosomal virulence gene, vacJ, required for intercellular spreading of Shigella flexneri. Suzuki T, Murai T, Fukuda I, Tobe T, Yoshikawa M, Sasakawa C; Mol Microbiol 1994;11:31-41. PMID:8145644