title: Determinants of the higher order association of the restriction factor TRIM5alpha and other tripartite motif (TRIM) proteins.
abstract: Many tripartite motif (TRIM) proteins self-associate, forming dimers and higher order complexes. For example, dimers of TRIM5α, a host factor that restricts retrovirus infection, assemble into higher order arrays on the surface of the viral capsid, resulting in an increase in avidity. Here we show that the higher order association of different TRIM proteins exhibits a wide range of efficiencies. Homologous association (self-association) was more efficient than the heterologous association of different TRIM proteins, indicating that specificity determinants of higher order self-association exist. To investigate the structural determinants of higher order self-association, we studied TRIM mutants and chimeras. These studies revealed the following: 1) the RING domain contributes to the efficiency of higher order self-association, which enhances the binding of TRIM5α to the human immunodeficiency virus (HIV-1) capsid; 2) the RING and B-box 2 domains work together as a homologous unit to promote higher order association of dimers; 3) dimerization is probably required for efficient higher order self-association; 4) the Linker 2 region contributes to higher order self-association, independently of effects of Linker 2 changes on TRIM dimerization; and 5) for efficiently self-associating TRIM proteins, the B30.2(SPRY) domain is not required for higher order self-association. These results support a model in which both ends of the core TRIM dimer (RING-B-box 2 at one end and Linker 2 at the other) contribute to the formation of higher order arrays.
authors.affiliation: Department of Cancer Immunology and AIDS, Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts 02215, USA.
authors.forename: Xing
authors.initials: X
authors.lastname: Li
authors.forename: Darwin F
authors.initials: DF
authors.lastname: Yeung
authors.forename: Ann M
authors.initials: AM
authors.lastname: Fiegen
authors.forename: Joseph
authors.initials: J
authors.lastname: Sodroski
mesh_terms: D000818:Animals; D000090103:Antiviral Restriction Factors; D002213:Capsid / Q000378:metabolism*; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D002460:Cell Line; D015497:HIV-1 / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D008253:Macaca mulatta; D009154:Mutation; D011485:Protein Binding; D055503:Protein Multimerization; D017434:Protein Structure, Tertiary; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D000070584:Tripartite Motif Proteins; D044767:Ubiquitin-Protein Ligases
chemical_list: D000090103:Antiviral Restriction Factors; D002352:Carrier Proteins; D011993:Recombinant Fusion Proteins; D000070584:Tripartite Motif Proteins; C477346:TRIM5 protein, human; D044767:Ubiquitin-Protein Ligases