EEVD motif of heat shock cognate protein 70 contributes to bacterial uptake by trophoblast giant cells.
BACKGROUND
The uptake of abortion-inducing pathogens by trophoblast giant (TG) cells is a key event in infectious abortion. However, little is known about phagocytic functions of TG cells against the pathogens. Here we show that heat shock cognate protein 70 (Hsc70) contributes to bacterial uptake by TG cells and the EEVD motif of Hsc70 plays an important role in this.


METHODS
Brucella abortus and Listeria monocytogenes were used as the bacterial antigen in this study. Recombinant proteins containing tetratricopeptide repeat (TPR) domains were constructed and confirmation of the binding capacity to Hsc70 was assessed by ELISA. The recombinant TPR proteins were used for investigation of the effect of TPR proteins on bacterial uptake by TG cells and on pregnancy in mice.


RESULTS
The monoclonal antibody that inhibits bacterial uptake by TG cells reacted with the EEVD motif of Hsc70. Bacterial TPR proteins bound to the C-terminal of Hsc70 through its EEVD motif and this binding inhibited bacterial uptake by TG cells. Infectious abortion was also prevented by blocking the EEVD motif of Hsc70.


CONCLUSIONS
Our results demonstrate that surface located Hsc70 on TG cells mediates the uptake of pathogenic bacteria and proteins containing the TPR domain inhibit the function of Hsc70 by binding to its EEVD motif. These molecules may be useful in the development of methods for preventing infectious abortion.
Watanabe
Kenta
K
Department of Veterinary Public Health, Faculty of Agriculture, Yamaguchi University, Yamaguchi 753-8515, Japan. kentaw@yamaguchi-u.ac.jp
Tachibana
Masato
M
Kim
Suk
S
Watarai
Masahisa
M
D020816:Amino Acid Motifs; D000818:Animals; D000911:Antibodies, Monoclonal / Q000737:chemistry; D002003:Brucella abortus / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D015726:Giant Cells / Q000378:metabolism* / Q000382:microbiology*; D050883:HSC70 Heat-Shock Proteins / Q000737:chemistry* / Q000378:metabolism; D018840:HSP70 Heat-Shock Proteins / Q000737:chemistry* / Q000378:metabolism; D006801:Humans; D008089:Listeria monocytogenes / Q000378:metabolism*; D051379:Mice; D011485:Protein Binding; D011487:Protein Conformation; D011994:Recombinant Proteins / Q000737:chemistry; D014327:Trophoblasts / Q000378:metabolism* / Q000382:microbiology*
D000911:Antibodies, Monoclonal; D050883:HSC70 Heat-Shock Proteins; D018840:HSP70 Heat-Shock Proteins; D011994:Recombinant Proteins