Neisseria meningitidisOpc invasin binds to the cytoskeletal protein α-actinin

Abstract

SummaryNeisseria meningitidis Opc protein is an effective invasin for human endothelial cells. We have investigated novel human endothelial receptors targeted by Opc and observed that Opc-expressing bacteria interacted with a 100 kDa protein in wholecell lysates of human endothelial and epithelial cells. The identity of the protein was established as a-actinin by mass spectrometry. Opc expression was essential for the recognition of a-actinin whether provided in a purified form or in cell extracts. The interaction of the two proteins did not involve intermediate molecules. As there was no demonstrable expression of a-actinin on the surfaces of any of the eight cell lines studied, the likelihood of the interactions after meningococcal internalization was examined. Confocal imaging demonstrated considerable colocalization of N. meningitidis with a-actinin especially after a prolonged period of internalization. This may imply that bacteria and a-actinin initially occur in separate compartments and co-compartmentalization occurs progressively over the 8 h infection period used. In conclusion, these studies have identified a novel and an intracellular target for the N. meningitidis Opc invasin. Since a-actinin is a modulator of a variety of signalling pathways and of cytoskeletal functions, its targeting by Opc may enable bacteria to survive/translocate across endothelial barriers.

Identification and Therapeutic Potential of a Vitronectin Binding Region of Meningococcal Msf

“…gonorrhoeae , H . influenzae , Streptococcus pneumoniae and Moraxella catarrhalis express surface proteins that bind to Vn and are able to adhere to and invade epithelial and endothelial cells via Vn-binding cell surface integrins [ 23 , 37 – 41 ]. In addition, several of these proteins, via binding to Vn, increase bacterial resistance to killing in human serum.…”

The Meningococcal Cysteine Transport System Plays a Crucial Role in Neisseria meningitidis Survival in Human Brain Microvascular Endothelial Cells

“…The bacterial suspension was prepared in AM at an OD 600 of 0.05, which corresponded to approximately 5 × 10 6 CFU/100 μl. The multiplicity of infection (MOI) was 500, a condition previously used in other studies (45, 83), to examine efficient N. meningitidis internalization (33, 42).…”

Multiple Functions of Glutamate Uptake via Meningococcal GltT-GltM l -Glutamate ABC Transporter in Neisseria meningitidis Internalization into Human Brain Microvascular Endothelial Cells

“…AM(ϪS, ϪG) and AM(ϪS, ϪNa) were prepared from 2-fold-concentrated MCDB131 without glutamate and sodium chloride, which was specially manufactured by the Cell Science & Technology Institute (Japan). In a standard experiment, the bacterial suspension was prepared in AM [AM(ϪS), AM(ϪS, ϪG), or AM(ϪS, ϪNa) where indicated] at an optical density at 600 nm (OD 600 ) of 0.05, which corresponded to approximately 5 ϫ 10 6 CFU/100 l. The multiplicity of infection (MOI) was 500, a condition previously used in other studies (40,41), to examine efficient N. meningitidis internalization (39). If a lower MOI was required, the bacterial suspension was prepared by further dilution.…”