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Review
. 1998 Jul;72(7):5329-34.
doi: 10.1128/JVI.72.7.5329-5334.1998.

Polyomavirus T antigens: molecular chaperones for multiprotein complexes

J L Brodsky  1 , J M Pipas
Affiliations
Review

Polyomavirus T antigens: molecular chaperones for multiprotein complexes

J L Brodsky et al. J Virol. 1998 Jul.
No abstract available

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Figures

FIG. 1
FIG. 1
Genetic maps of SV40 and PyV. ori indicates position of the origin of DNA replication, PE is the early region promoter, PL is the late region promoter. Arrowed lines indicate coding sequences for viral proteins. Arrowhead indicates the carboxy terminus of the protein. LT, large T antigen; MT, middle T antigen; ST, small t antigen; and, TT, tiny t antigen.
FIG. 2
FIG. 2
SV40 early region. Structure of the three early mRNAs is shown, along with a simplified domain map of the viral T antigens. Numbers above the line indicate SV40 genomic nucleotide position. Numbers below the line indicate amino acid position from the amino terminus of T antigen. Rb, retinoblastoma family-binding domain; p53, p53-binding region; pp2A, protein phosphatase 2A- binding domain.
FIG. 3
FIG. 3
Depiction of the SV40 T-antigen J domain. I, II, III, and IV indicate α-helices as determined by sequence comparisons and secondary structure predictions. Positions of mutations in SV40 mutants 5110, dl1135, C6-1, C6-1R, and 5002 are shown. Although Spence and Pipas reported that 5002 was a double amino acid substitution mutant (42), subsequent studies have determined that the defective phenotype is due solely to the L19F change.
FIG. 4
FIG. 4
Model for T-antigen chaperone action on a multiprotein complex. First, T antigen recruits ATP-bound hsc70 via the J domain and the target protein complex via a substrate-binding domain into an activated complex (asterisk). Next, energy derived from hsc70-mediated ATP hydrolysis induces a conformational change in one or more members of the target complex. This is followed by release of hsc70 and the altered target that can now act as an effector for downstream signaling events. II, III, and IV, J-domain α-helices.
See this image and copyright information in PMC

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