Proteolytic processing is required for viral superantigen activity.
The mouse mammary tumor virus-7 superantigen (vSAG7) is proteolytically processed in B cells at as many as three positions. Proteolytic processing appears to be important for superantigen activity because a processed form of vSAG7 was predominant among those forms that were found to bind to major histocompatibility complex class II molecules. To determine the functional significance of proteolytic processing, a mutation was introduced in vSAG7 at one of the sites where proteolytic cleavage is thought to take place in B cells. Elimination of the putative processing site at position 171 abrogated detectable vSAG7 surface expression in B cells, indicating that proteolytic processing is required for vSAG7 function. Coexpression in insect cells of vSAG7 and furin, a proprotein-processing enzyme, also demonstrated that furin could process vSAG7 at position 171.
Park
C G
CG
Rockefeller University, New York 10021, USA.
Jung
M Y
MY
Choi
Y
Y
Winslow
G M
GM
D000595:Amino Acid Sequence; D000818:Animals; D017951:Antigen Presentation; D000956:Antigens, Viral / Q000378:metabolism*; D001483:Base Sequence; D045683:Furin; D017988:Gammaretrovirus / Q000276:immunology*; D008969:Molecular Sequence Data; D018411:Spodoptera; D013381:Subtilisins / Q000378:metabolism; D018089:Superantigens / Q000378:metabolism*; D014407:Tumor Cells, Cultured
D000956:Antigens, Viral; D018089:Superantigens; D013381:Subtilisins; D045683:Furin