TY - JOUR
T1 - Phosphoglycerate kinase inhibits epithelial cell invasion by group B streptococci
AU - Burnham, Carey Ann D.
AU - Shokoples, Sandra E.
AU - Tyrrell, Gregory J.
N1 - Funding Information:
We would like to acknowledge B. Brett Finlay for suggesting the use of α-actinin antibodies to examine the recruitment of host cell α-actinin to binding sites of GBS on epithelial cells. This work was supported in part by a University of Alberta Hospital Foundation/Alberta Health Sciences Research Institute grant and a Children's Health Foundation of Northern Alberta grant. C.D.B. is a recipient of a University of Alberta Faculty of Medicine and Dentistry Medical Sciences Graduate Program Graduate Research Assistantship and a Natural Sciences and Engineering Research Council of Canada Postgraduate Doctoral Scholarship.
PY - 2005/5
Y1 - 2005/5
N2 - Group B streptococci (GBS) are opportunistic human pathogens that cause infection and invasive disease in newborns, pregnant women and non-pregnant adults. The internalization of GBS into eukaryotic cells occurs in an actin-microfilament dependant process. The objective of our study was to understand what host cell and/or bacterial factors may be involved in this process. We focused on α-actinin, an actin binding protein closely associated with cytoplamsic F-actin in the eukaryotic cell, to determine if it is involved in actin recruitment upon GBS internalization. Initial work revealed that GBS does not recruit α-actinin. However, it was found that α-actinin antibodies bound to the surface of the GBS, suggesting GBS possess surface-exposed actin binding protein(s). Slide agglutination experiments revealed that when the bacteria were emulsified with F-actin, visible agglutination occurred, further suggesting the presence of an actin binding protein on the GBS cell. Western blot analysis found that anti-α-actinin antibodies bound to a 42 kDa protein; mass spectra analysis identified this protein as GBS phosphoglycerate kinase (PGK). Competitive binding assays suggest that the PGK-actin interaction is not a factor in the initial binding of GBS to epithelial cells, however, treating epithelial cells with PGK prior to performing an invasion assay inhibited GBS internalization. This occurred in a dose dependant manner with 10 μg/mL of PGK inhibiting invasion by over 70%, and 50 μg/mL PGK inhibits GBS invasion completely.
AB - Group B streptococci (GBS) are opportunistic human pathogens that cause infection and invasive disease in newborns, pregnant women and non-pregnant adults. The internalization of GBS into eukaryotic cells occurs in an actin-microfilament dependant process. The objective of our study was to understand what host cell and/or bacterial factors may be involved in this process. We focused on α-actinin, an actin binding protein closely associated with cytoplamsic F-actin in the eukaryotic cell, to determine if it is involved in actin recruitment upon GBS internalization. Initial work revealed that GBS does not recruit α-actinin. However, it was found that α-actinin antibodies bound to the surface of the GBS, suggesting GBS possess surface-exposed actin binding protein(s). Slide agglutination experiments revealed that when the bacteria were emulsified with F-actin, visible agglutination occurred, further suggesting the presence of an actin binding protein on the GBS cell. Western blot analysis found that anti-α-actinin antibodies bound to a 42 kDa protein; mass spectra analysis identified this protein as GBS phosphoglycerate kinase (PGK). Competitive binding assays suggest that the PGK-actin interaction is not a factor in the initial binding of GBS to epithelial cells, however, treating epithelial cells with PGK prior to performing an invasion assay inhibited GBS internalization. This occurred in a dose dependant manner with 10 μg/mL of PGK inhibiting invasion by over 70%, and 50 μg/mL PGK inhibits GBS invasion completely.
KW - Actin
KW - Actin binding proteins
KW - Group B streptococcus
KW - HeLa cells
KW - Phosphoglycerate kinase
KW - α-Actinin
UR - http://www.scopus.com/inward/record.url?scp=19544389507&partnerID=8YFLogxK
U2 - 10.1016/j.micpath.2005.02.002
DO - 10.1016/j.micpath.2005.02.002
M3 - Article
C2 - 15925270
AN - SCOPUS:19544389507
SN - 0882-4010
VL - 38
SP - 189
EP - 200
JO - Microbial Pathogenesis
JF - Microbial Pathogenesis
IS - 5-6
ER -