Lipoteichoic acid
This article needs attention from an expert in Microbiology.(May 2009) |
Lipoteichoic acid (LTA) is a major constituent of the cell wall of gram-positive bacteria. These organisms have an inner (or cytoplasmic) membrane and, external to it, a thick (up to 80 nanometer) peptidoglycan layer. The structure of LTA varies between the different species of Gram-positive bacteria and may contain long chains of ribitol or glycerol phosphate. LTA is anchored to the cell membrane via a diacylglycerol.[1] It acts as regulator of autolytic wall enzymes (muramidases). It has antigenic properties being able to stimulate specific immune response.
LTA may bind to target cells non-specifically through membrane phospholipids, or specifically to CD14 and to Toll-like receptors. Binding to TLR-2 has shown to induce NF-κB expression(a central transcription factor), elevating expression of both pro- and anti-apoptotic genes. Its activation also induces mitogen-activated protein kinases (MAPK) activation along with phosphoinositide 3-kinase activation.
Studies[]
LTA's molecular structure has been found to have the strongest hydrophobic bonds of an entire bacteria[citation needed].
Said et al. showed that LTA causes an IL-10-dependent inhibition of CD4 T-cell expansion and function by up-regulating PD-1 levels on monocytes which leads to IL-10 production by monocytes after binding of PD-1 by PD-L.[2]
References[]
- Department of Oral Biology, Hebrew University-Hadassah Faculty of Dental Medicine, Ein-Kerem Campus, Jerusalem, Israel.
External links[]
- lipoteichoic+acid at the US National Library of Medicine Medical Subject Headings (MeSH)
- Organic acids
- Cell biology