Conserved asymmetry underpins homodimerization of Dicer-associated double-stranded RNA-binding proteins

TY - JOUR

T1 - Conserved asymmetry underpins homodimerization of Dicer-associated double-stranded RNA-binding proteins

AU - Heyam, Alex

AU - Coupland, Claire E

AU - Dégut, Clément

AU - Haley, Ruth A

AU - Baxter, Nicola J

AU - Jakob, Leonhard

AU - Aguiar, Pedro M.

AU - Meister, Gunter

AU - Williamson, Michael P.

AU - Lagos, Dimitris

AU - Plevin, Michael J

N1 - © 2017 Oxford University Press. This is an author-produced version of the published paper. Uploaded in accordance with the publisher’s self-archiving policy. Further copying may not be permitted; contact the publisher for details.

PY - 2017/12/1

Y1 - 2017/12/1

N2 - Double-stranded RNA-binding domains (dsRBDs) are commonly found in modular proteins that interact with RNA. Two varieties of dsRBD exist: canonical Type A dsRBDs interact with dsRNA, while non-canonical Type B dsRBDs lack RNA-binding residues and instead interact with other proteins. In higher eukaryotes, the microRNA biogenesis enzyme Dicer forms a 1:1 association with a dsRNA-binding protein (dsRBP). Human Dicer associates with HIV TAR RNA-binding protein (TRBP) or protein activator of PKR (PACT), while Drosophila Dicer-1 associates with Loquacious (Loqs). In each case, the interaction involves a region of the protein that contains a Type B dsRBD. All three dsRBPs are reported to homodimerize, with the Dicer-binding region implicated in self-association. We report that these dsRBD homodimers display structural asymmetry and that this unusual self-association mechanism is conserved from flies to humans. We show that the core dsRBD is sufficient for homodimerization and that mutation of a conserved leucine residue abolishes self-association. We attribute differences in the self-association properties of Loqs, TRBP and PACT to divergence of the composition of the homodimerization interface. Modifications that make TRBP more like PACT enhance self-association. These data are examined in the context of miRNA biogenesis and the protein/protein interaction properties of Type B dsRBDs.

AB - Double-stranded RNA-binding domains (dsRBDs) are commonly found in modular proteins that interact with RNA. Two varieties of dsRBD exist: canonical Type A dsRBDs interact with dsRNA, while non-canonical Type B dsRBDs lack RNA-binding residues and instead interact with other proteins. In higher eukaryotes, the microRNA biogenesis enzyme Dicer forms a 1:1 association with a dsRNA-binding protein (dsRBP). Human Dicer associates with HIV TAR RNA-binding protein (TRBP) or protein activator of PKR (PACT), while Drosophila Dicer-1 associates with Loquacious (Loqs). In each case, the interaction involves a region of the protein that contains a Type B dsRBD. All three dsRBPs are reported to homodimerize, with the Dicer-binding region implicated in self-association. We report that these dsRBD homodimers display structural asymmetry and that this unusual self-association mechanism is conserved from flies to humans. We show that the core dsRBD is sufficient for homodimerization and that mutation of a conserved leucine residue abolishes self-association. We attribute differences in the self-association properties of Loqs, TRBP and PACT to divergence of the composition of the homodimerization interface. Modifications that make TRBP more like PACT enhance self-association. These data are examined in the context of miRNA biogenesis and the protein/protein interaction properties of Type B dsRBDs.

KW - Humans

KW - Models, Molecular

KW - Nuclear Magnetic Resonance, Biomolecular

KW - Protein Domains

KW - Protein Multimerization

KW - RNA, Double-Stranded

KW - RNA-Binding Proteins

KW - Journal Article

U2 - 10.1093/nar/gkx928

DO - 10.1093/nar/gkx928

M3 - Article

C2 - 29045748

SN - 0305-1048

VL - 45

SP - 12577

EP - 12584

JO - Nucleic Acids Research

JF - Nucleic Acids Research

IS - 21

ER -