P31793 (ENV_FRSFB) Reviewed, UniProtKB/Swiss-Prot
Last modified October 16, 2013. Version 78. History...
Names and origin
|Protein names||Recommended name:|
|Organism||Friend spleen focus-forming virus (strain BB6) (FSFFV)|
|Taxonomic identifier||31692 [NCBI]|
|Taxonomic lineage||Viruses › Retro-transcribing viruses › Retroviridae › Orthoretrovirinae › Gammaretrovirus › unclassified Gammaretrovirus ›|
|Virus host||Mus musculus (Mouse) [TaxID: 10090]|
|Sequence length||356 AA.|
|Sequence processing||The displayed sequence is further processed into a mature form.|
|Protein existence||Inferred from homology|
General annotation (Comments)
This envelope-like membrane glycoprotein is responsible for ligand-independent activation of the erythropoietin receptor EPOR leading to the abnormally rapid proliferation of erythroid precursor cells. In the first stage of Friend disease, constitutive activation of the EPOR by gp42 causes uncontrolled, polyclonal proliferation of infected erythroblasts, leading to polycythemia (massive increase in the number of mature red cells). Host susceptibility to SSFV-induced erythroblastosis usually depends on the expression of the truncated isoform of MST1R receptor tyrosine kinase (MST1R isoform sf-Stk), but the deletion mutant BB6 apparently can overcome its absence.
Homooligomer. Forms heterooligomers with mouse EPOR, probably via their respective transmembrane domains. BB6 deletion mutant does not interact with mouse MST1R isoform sf-Stk.
Host endoplasmic reticulum membrane; Single-pass type I membrane protein. Host cell membrane; Single-pass type I membrane protein. Virion membrane; Single-pass type I membrane protein. Note: The envelope-like membrane glycoprotein gp55 is defective in its transport to the cell surface and remains associated predominantly with the rough endoplasmic reticulum (RER) membrane. It is almost not incorporated into virions. Host cell surface expression appears to be a prerequisite for its leukemogenicity By similarity.
Compared to other gammaretroviruses which possess 2 envelope proteins (gp70 and p15E), FSFFV gp55 corresponds to a gp70-p15E fusion protein with a deletion of a portion of p15E. It is encoded by the defective env gene of the virus. Strain BB6 gp42 is a truncated form of gp55.
The Friend murine leukemia virus complex induces a rapid and fatal erythroleukemia in adult mice. It is the replication-defective spleen focus-forming virus (SFFV) contained in this complex that causes foci of proliferating erythroid cells in spleens of infected mice. The second component is a replication competent Friend murine leukemia virus (F-MuLV) that serves as a helper virus for SFFV.
Sequence annotation (Features)
|Feature key||Position(s)||Length||Description||Graphical view||Feature identifier|
|Signal peptide||1 – 32||32||Potential|
|Chain||33 – 356||324||Glycoprotein 42||PRO_0000040722|
|Topological domain||33 – 331||299||Virion surface Potential|
|Transmembrane||332 – 352||21||Helical; Potential|
|Topological domain||353 – 356||4||Intravirion Potential|
|Motif||306 – 309||4||CXXC|
|Compositional bias||229 – 278||50||Pro-rich|
Amino acid modifications
|Glycosylation||43||1||N-linked (GlcNAc...); by host Potential|
|Glycosylation||58||1||N-linked (GlcNAc...); by host Potential|
|Glycosylation||296||1||N-linked (GlcNAc...); by host Potential|
|Glycosylation||328||1||N-linked (GlcNAc...); by host Potential|
|||"Mutations in the env gene of friend spleen focus-forming virus overcome Fv-2r-mediated resistance to Friend virus-induced erythroleukemia."|
Majumdar M.K., Cho C.L., Fox M.T., Eckner K.L., Kozak S., Kabat D., Geib R.W.
J. Virol. 66:3652-3660(1992) [PubMed] [Europe PMC] [Abstract]
Cited for: NUCLEOTIDE SEQUENCE [GENOMIC DNA].
|M90673 Genomic DNA. No translation available.|
|PIR||VCVWB6. A41995. |
3D structure databases
|SMR||P31793. Positions 38-229. |
Protocols and materials databases
Family and domain databases
|Gene3D||3.90.310.10. 1 hit. |
|InterPro||IPR008981. FMuLV_rcpt-bd. |
|PANTHER||PTHR10424. PTHR10424. 1 hit. |
|Pfam||PF00429. TLV_coat. 2 hits. |
|SUPFAM||SSF49830. SSF49830. 1 hit. |
|Accession||Primary (citable) accession number: P31793|
|Entry status||Reviewed (UniProtKB/Swiss-Prot)|
|Annotation program||Viral Protein Annotation Program|