A novel mechanism for protein delivery: granzyme B undergoes electrostatic exchange from serglycin to target cells.
The molecular interaction of secreted granzyme B-serglycin complexes with target cells remains undefined. Targets exposed to double-labeled granzyme B-serglycin complexes show solely the uptake of granzyme B. An in vitro model demonstrates the exchange of the granzyme from serglycin to immobilized, sulfated glycosaminoglycans. Using a combination of cell binding and internalization assays, granzyme B was found to exchange to sulfated glycosaminoglycans and, depending on the cell type, to higher affinity sites. Apoptosis induced by purified granzyme B and cytotoxic T-cells was diminished in targets with reduced cell surface glycosaminoglycan content. A mechanism of delivery is proposed entailing electrostatic transfer of granzyme B from serglycin to cell surface proteins.
Raja
Srikumar M
SM
Department of Medicine, Evanston Northwestern Healthcare Research Institute, Evanston, Illinois 60201, USA. s-raja@northwestern.edu
Metkar
Sunil S
SS
Höning
Stefan
S
Wang
Baikun
B
Russin
William A
WA
Pipalia
Nina H
NH
Menaa
Cheikh
C
Belting
Mattias
M
Cao
Xuefang
X
Dressel
Ralf
R
Froelich
Christopher J
CJ
D000818:Animals; D017209:Apoptosis; D001692:Biological Transport; D016466:CHO Cells; D002462:Cell Membrane / Q000737:chemistry / Q000378:metabolism*; D006224:Cricetinae; D005434:Flow Cytometry; D006025:Glycosaminoglycans / Q000032:analysis / Q000378:metabolism; D053804:Granzymes; D018922:HL-60 Cells; D006801:Humans; D019169:Jurkat Cells; D008565:Membrane Proteins / Q000378:metabolism; D051379:Mice; D008822:Mice, Transgenic; D011509:Proteoglycans / Q000032:analysis / Q000737:chemistry* / Q000378:metabolism* / Q000502:physiology; D011948:Receptors, Antigen, T-Cell / Q000235:genetics; D012697:Serine Endopeptidases / Q000032:analysis / Q000737:chemistry* / Q000378:metabolism*; D055672:Static Electricity; D013431:Sulfates / Q000378:metabolism; D013602:T-Lymphocytes, Cytotoxic / Q000502:physiology; D033921:Vesicular Transport Proteins
D006025:Glycosaminoglycans; D008565:Membrane Proteins; D011509:Proteoglycans; D011948:Receptors, Antigen, T-Cell; D013431:Sulfates; D033921:Vesicular Transport Proteins; C075430:serglycin; C509213:GZMB protein, human; D053804:Granzymes; C509214:Gzmb protein, mouse; D012697:Serine Endopeptidases