Vaccinia virus L1 binds to cell surfaces and blocks virus entry independently of glycosaminoglycans.
L1 and A28 are vaccinia virus (VACV) envelope proteins which are essential for cellular entry. However, their specific roles during entry are unknown. We tested whether one or both of these proteins might serve as receptor binding proteins (RBP). We found that a soluble, truncated form of L1, but not A28, bound to cell surfaces independently of glycosaminoglycans (GAGs). Hence, VACV A28 is not likely to be a RBP and functions after attachment during entry. Importantly, soluble L1 inhibited both binding and entry of VACV in GAG-deficient cells, suggesting that soluble L1 blocks entry at the binding step by competing with the virions for non-GAG receptors on cells. In contrast, soluble A27, a VACV protein which attaches to GAGs but is non-essential for virus entry, inhibited binding and entry of VACV in a GAG-dependent manner. To our knowledge, this is the first report of a VACV envelope protein that blocks virus binding and entry independently of GAGs.
Foo
Chwan Hong
CH
Department of Microbiology, School of Dental Medicine, University of Pennsylvania, 240 S. 40th St, Levy Rm 233, Philadelphia, PA 19104, USA. chfoo@mail.med.upenn.edu
Lou
Huan
H
Whitbeck
J Charles
JC
Ponce-de-León
Manuel
M
Atanasiu
Doina
D
Eisenberg
Roselyn J
RJ
Cohen
Gary H
GH
D000818:Animals; D000914:Antibodies, Viral / Q000378:metabolism; D002352:Carrier Proteins / Q000378:metabolism; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism / Q000821:virology; D002522:Chlorocebus aethiops; D005347:Fibroblasts / Q000821:virology; D006025:Glycosaminoglycans / Q000037:antagonists & inhibitors / Q000378:metabolism*; D006367:HeLa Cells; D006801:Humans; D008565:Membrane Proteins; D051379:Mice; D011991:Receptors, Virus / Q000378:metabolism*; D014615:Vaccinia / Q000821:virology; D014616:Vaccinia virus / Q000276:immunology / Q000378:metabolism / Q000502:physiology*; D014709:Vero Cells; D014759:Viral Envelope Proteins / Q000276:immunology / Q000302:isolation & purification / Q000378:metabolism*; D014760:Viral Fusion Proteins / Q000378:metabolism; D053585:Virus Attachment; D053586:Virus Internalization
C526377:A27 protein, vaccinia virus; D000914:Antibodies, Viral; D002352:Carrier Proteins; D006025:Glycosaminoglycans; C087715:L1R protein, Vaccinia virus; D008565:Membrane Proteins; D011991:Receptors, Virus; D014759:Viral Envelope Proteins; D014760:Viral Fusion Proteins