Extracellular HspBP1 inhibits formation of a cytotoxic Tag7-Hsp70 complex in vitro and in human serum.
Tag7 (PGRP-S) was described as an innate immunity protein. Earlier we have shown that Tag7 forms with Hsp70 a stable complex with cytotoxic and antitumor activity. The same complex is formed in and secreted by cytotoxic T-lymphocytes. We have also found that Hsp-binding protein HspBP1 incapacitates the Tag7-Hsp70 complex. Here we have studied the interaction of extracellular Tag7 and HspBP1. We have shown that HspBP1 binds Tag7 in the conditioned medium of tumor CSML0 cells, thereby preventing formation of the cytotoxic Tag7-Hsp70 complex. We have also found that Tag7, if present in serum (in every third donor on average), is always in complex with HspBP1. This may be a protective measure against indiscriminate attack of the cytotoxic complex on normal cells.
Institute of Gene Biology, Russian Academy of Sciences (RAS), Moscow 119344, Russia.
Denis V
DV
Yashin
Elena A
EA
Dukhanina
Olga D
OD
Kabanova
Elena A
EA
Romanova
Tamara I
TI
Lukyanova
Alexsander G
AG
Tonevitskii
Alexey A
AA
Belogurov
Deborah A
DA
Raynes
Anton A
AA
Sheludchenkov
Nikolai V
NV
Gnuchev
Vince
V
Guerriero
Georgii P
GP
Georgiev
Lidia P
LP
Sashchenko
D048868:Adaptor Proteins, Signal Transducing / Q000502:physiology*; D045744:Cell Line, Tumor; D017077:Culture Media, Conditioned; D016207:Cytokines / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D018840:HSP70 Heat-Shock Proteins / Q000378:metabolism*; D006801:Humans; D066298:In Vitro Techniques
D048868:Adaptor Proteins, Signal Transducing; D017077:Culture Media, Conditioned; D016207:Cytokines; D018840:HSP70 Heat-Shock Proteins; C116331:HSPBP1 protein, human; C491878:PGLYRP1 protein, human