The Bartonella henselae VirB/Bep System

Link: http://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&id=21044238&retmode=ref&cmd=prlinks

Excerpt:

On the molecular level,
Bh infection did not alter VEGF-receptor-2
(VEGFR2) expression or cell surface localization, but impeded
VEGF-stimulated phosphorylation of VEGFR2 at tyrosine(1175) .
Consistently, we observed that Bh infection diminished downstream
events of the tyrosine(1175) -dependent VEGFR2-signalling pathway
leading to EC proliferation, i.e. phospholipase-Cgamma
activation, cytosolic calcium fluxes, and mitogen-activated
protein kinase
ERK1/2 phosphorylation. Pervanadate-treatment neutralized the
inhibitory activity of Bh on VEGF signalling, suggesting that Bh
infection may activate a phosphatase that alleviates VEGFR2
phosphorylation. Inhibition of VEGFR2 signalling by Bh infection
was strictly dependent on a functional VirB type IV secretion
system and thereby translocated Bep effector proteins.
The data
presented in this study underscore the role of the VirB/Bep
system as important factor controlling EC proliferation in
response to Bh infection; not only as previously reported by
counter-acting an intrinsic bacterial mitogenic stimulus, but
also by restricting the exogenous angiogenic stimulation by
Bh-induced VEGF.