A sliding docking interaction is essential for sequential and processive phosphorylation of an SR protein by SRPK1.
The 2.9 A crystal structure of the core SRPK1:ASF/SF2 complex reveals that the N-terminal half of the basic RS domain of ASF/SF2, which is destined to be phosphorylated, is bound to an acidic docking groove of SRPK1 distal to the active site. Phosphorylation of ASF/SF2 at a single site in the C-terminal end of the RS domain generates a primed phosphoserine that binds to a basic site in the kinase. Biochemical experiments support a directional sliding of the RS peptide through the docking groove to the active site during phosphorylation, which ends with the unfolding of a beta strand of the RRM domain and binding of the unfolded region to the docking groove. We further suggest that the priming of the first serine facilitates directional substrate translocation and efficient phosphorylation.
Ngo
Jacky Chi Ki
JC
Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA.
Giang
Kayla
K
Chakrabarti
Sutapa
S
Ma
Chen-Ting
CT
Huynh
Nhat
N
Hagopian
Jonathan C
JC
Dorrestein
Pieter C
PC
Fu
Xiang-Dong
XD
Adams
Joseph A
JA
Ghosh
Gourisankar
G
D000266:Adenylyl Imidodiphosphate / Q000737:chemistry / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D018360:Crystallography, X-Ray; D006801:Humans; D051379:Mice; D008958:Models, Molecular; D008969:Molecular Sequence Data; D046912:Multiprotein Complexes / Q000378:metabolism; D009687:Nuclear Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D010766:Phosphorylation; D011485:Protein Binding; D017346:Protein Serine-Threonine Kinases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D016601:RNA-Binding Proteins; D012262:Ribonucleoside Diphosphate Reductase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D000068103:Serine-Arginine Splicing Factors
D046912:Multiprotein Complexes; D009687:Nuclear Proteins; D016601:RNA-Binding Proteins; D000068103:Serine-Arginine Splicing Factors; D000266:Adenylyl Imidodiphosphate; C093713:ribonucleotide reductase M2; D012262:Ribonucleoside Diphosphate Reductase; C087728:SRPK1 protein, human; D017346:Protein Serine-Threonine Kinases