Intra-domain Cross-talk Regulates Serine-arginine Protein Kinase 1-dependent Phosphorylation and Splicing Function of Transformer 2ß1.
J Biol Chem
; 290(28): 17269-81, 2015 Jul 10.
Article
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| MEDLINE
| ID: mdl-26013829
ABSTRACT
Transformer 2ß1 (Tra2ß1) is a splicing effector protein composed of a core RNA recognition motif flanked by two arginine-serine-rich (RS) domains, RS1 and RS2. Although Tra2ß1-dependent splicing is regulated by phosphorylation, very little is known about how protein kinases phosphorylate these two RS domains. We now show that the serine-arginine protein kinase-1 (SRPK1) is a regulator of Tra2ß1 and promotes exon inclusion in the survival motor neuron gene 2 (SMN2). To understand how SRPK1 phosphorylates this splicing factor, we performed mass spectrometric and kinetic experiments. We found that SRPK1 specifically phosphorylates 21 serines in RS1, a process facilitated by a docking groove in the kinase domain. Although SRPK1 readily phosphorylates RS2 in a splice variant lacking the N-terminal RS domain (Tra2ß3), RS1 blocks phosphorylation of these serines in the full-length Tra2ß1. Thus, RS2 serves two new functions. First, RS2 positively regulates binding of the central RNA recognition motif to an exonic splicing enhancer sequence, a phenomenon reversed by SRPK1 phosphorylation on RS1. Second, RS2 enhances ligand exchange in the SRPK1 active site allowing highly efficient Tra2ß1 phosphorylation. These studies demonstrate that SRPK1 is a regulator of Tra2ß1 splicing function and that the individual RS domains engage in considerable cross-talk, assuming novel functions with regard to RNA binding, splicing, and SRPK1 catalysis.
Palabras clave
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Proteínas de Unión al ARN
/
Proteínas Serina-Treonina Quinasas
/
Proteínas del Tejido Nervioso
Límite:
Humans
Idioma:
En
Revista:
J Biol Chem
Año:
2015
Tipo del documento:
Article