RNA Interference Screen Identifies Abl Kinase and PDGFR Signaling in Chlamydia trachomatis Entry

PLoS Pathogens

Jung Hwa Kim¹  Cherilyn A. Elwell¹  Alhaji Ceesay¹  Joanne N. Engel¹  Daniel Kalman² 

[1] Department of Medicine, University of California San Francisco, San Francisco, California, United States of America;Department of Pathology and Laboratory of Medicine, Emory University, Atlanta, Georgia, United States of America

关键词: Chlamydia trachomatis;    Phosphorylation;    Tyrosine;    Chlamydia infection;    Tyrosine kinases;    Cell staining;    HeLa cells;    Host cells;   

DOI  :  10.1371/journal.ppat.1000021

学科分类：生物科学（综合）

来源: Public Library of Science

【 摘 要 】

To elucidate the mechanisms involved in early events in Chlamydia trachomatis infection, we conducted a large scale unbiased RNA interference screen in Drosophila melanogaster S2 cells. This allowed identification of candidate host factors in a simple non-redundant, genetically tractable system. From a library of 7,216 double stranded RNAs (dsRNA), we identified ∼226 host genes, including two tyrosine kinases, Abelson (Abl) kinase and PDGF- and VEGF-receptor related (Pvr), a homolog of the Platelet-derived growth factor receptor (PDGFR). We further examined the role of these two kinases in C. trachomatis binding and internalization into mammalian cells. Both kinases are phosphorylated upon infection and recruited to the site of bacterial attachment, but their roles in the infectious process are distinct. We provide evidence that PDGFRβ may function as a receptor, as inhibition of PDGFRβ by RNA interference or by PDGFRβ neutralizing antibodies significantly reduces bacterial binding, whereas depletion of Abl kinase has no effect on binding. Bacterial internalization can occur through activation of PDGFRβ or through independent activation of Abl kinase, culminating in phosphorylation of the Rac guanine nucleotide exchange factor (GEF), Vav2, and two actin nucleators, WAVE2 and Cortactin. Finally, we show that TARP, a bacterial type III secreted actin nucleator implicated in entry, is a target of Abl kinase. Together, our results demonstrate that PDGFRβ and Abl kinases function redundantly to promote efficient uptake of this obligate intracellular parasite.

【 授权许可】

CC BY