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Stimulation of poly(A) polymerase through a direct interaction with the nuclear poly(A) binding protein allosterically regulated by RNA
Author(s) -
Kerwitz Yvonne,
Kühn Uwe,
Lilie Hauke,
Knoth Anne,
Scheuermann Till,
Friedrich Henning,
Schwarz Elisabeth,
Wahle Elmar
Publication year - 2003
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1093/emboj/cdg347
Subject(s) - polymerase , polyadenylation , biology , poly(a) binding protein , rna polymerase , rna polymerase ii , allosteric regulation , rna , microbiology and biotechnology , biochemistry , enzyme , rna binding protein , gene expression , gene , promoter
During polyadenylation of mRNA precursors in metazoan cells, poly(A) polymerase is stimulated by the nuclear poly(A) binding protein PABPN1. We report that stimulation depends on binding of PABPN1 to the substrate RNA directly adjacent to poly(A) polymerase and results in an ∼80‐fold increase in the apparent affinity of poly(A) polymerase for RNA without significant effect on catalytic efficiency. PABPN1 associates directly with poly(A) polymerase either upon allosteric activation by oligo(A) or, in the absence of RNA, upon deletion of its N‐terminal domain. The N‐terminal domain of PABPN1 may function to inhibit undesirable interactions of the protein; the inhibition is relieved upon RNA binding. Tethering of poly(A) polymerase is mediated largely by the C‐terminal domain of PABPN1 and is necessary but not sufficient for stimulation of the enzyme; an additional interaction dependent on a coiled‐coil structure located within the N‐terminal domain of PABPN1 is required for a productive interaction.