Receptors and entry cofactors for retroviruses include single and multiple transmembrane-spanning proteins as well as newly described glycophosphatidylinositol-anchored and secreted proteins.
In the past few years, many retrovirus receptors, coreceptors, and cofactors have been identified. These molecules are important for some aspects of viral entry, although in some cases it remains to be determined whether they are required for binding or postbinding stages in entry, such as fusion. There are certain common features to the molecules that many retroviruses use to gain entry into the cell. For example, the receptors for most mammalian oncoretroviruses are multiple membrane-spanning transport proteins. However, avian retroviruses use single-pass membrane proteins, and a sheep retrovirus uses a glycosylphosphatidylinositol-anchored molecule as its receptor. For some retroviruses, particularly the lentiviruses, two cell surface molecules are required for efficient entry. More recently, a soluble protein that is required for viral entry has been identified for a feline oncoretrovirus. In this review, we will focus on the various strategies used by mammalian retroviruses to gain entry into the cell. The choice of receptors will also be discussed in light of pressures that drive viral evolution and persistence.
Overbaugh
J
J
Division of Human Biology, Fred Hutchinson Cancer Research Center, 1100 Fairview Ave., Seattle, WA 98109-1024, USA. joverbau@fhcrc.org
Miller
A D
AD
Eiden
M V
MV
D048868:Adaptor Proteins, Signal Transducing; D000818:Animals; D015704:CD4 Antigens; D002352:Carrier Proteins; D018797:Cell Cycle Proteins; D017261:Glycosylphosphatidylinositols / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D008561:Membrane Fusion; D008565:Membrane Proteins / Q000378:metabolism*; D010750:Phosphoproteins; D011991:Receptors, Virus / Q000378:metabolism*; D012190:Retroviridae / Q000235:genetics / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid; D014759:Viral Envelope Proteins / Q000235:genetics / Q000378:metabolism
D048868:Adaptor Proteins, Signal Transducing; D015704:CD4 Antigens; D002352:Carrier Proteins; D018797:Cell Cycle Proteins; C485647:GIT1 protein, human; D017261:Glycosylphosphatidylinositols; D008565:Membrane Proteins; D010750:Phosphoproteins; D011991:Receptors, Virus; D014759:Viral Envelope Proteins; C067981:leukemia virus receptor, gibbon ape