Crystal structure of a SFPQ/PSPC1 heterodimer provides insights into preferential heterodimerization of human DBHS family proteins

Jie Huang, G Patricia Casas Garcia, Matthew A Perugini, Archa H Fox, Charles S Bond, Mihwa Lee

Research output: Contribution to journalArticle

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Abstract

Members of the Drosophila behavior human splicing (DBHS) protein family are nuclear proteins implicated in many layers of nuclear functions, including RNA biogenesis as well as DNA repair. Definitive of the DBHS protein family, the conserved DBHS domain provides a dimerization platform that is critical for the structural integrity and function of these proteins. The three human DBHS proteins, splicing factor proline- and glutamine-rich (SFPQ), paraspeckle component 1 (PSPC1), and non-POU domain-containing octamer-binding protein (NONO), form either homo- or heterodimers; however, the relative affinity and mechanistic details of preferential heterodimerization are yet to be deciphered. Here we report the crystal structure of a SFPQ/PSPC1 heterodimer to 2.3-Å resolution and analyzed the subtle structural differences between the SFPQ/PSPC1 heterodimer and the previously characterized SFPQ homodimer. Analytical ultracentrifugation to estimate the dimerization equilibrium of the SFPQ-containing dimers revealed that the SFPQ-containing dimers dissociate at low micromolar concentrations and that the heterodimers have higher affinities than the homodimer. Moreover, we observed that the apparent dissociation constant for the SFPQ/PSPC1 heterodimer was over 6-fold lower than that of the SFPQ/NONO heterodimer. We propose that these differences in dimerization affinity may represent a potential mechanism by which PSPC1 at a lower relative cellular abundance can outcompete NONO to heterodimerize with SFPQ.

LanguageEnglish
Pages6593-6602
Number of pages10
JournalThe Journal of Biological Chemistry
Volume293
Issue number17
DOIs
StatePublished - 27 Apr 2018

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Protein Splicing
Drosophila
Dimerization
Crystal structure
Dimers
Proteins
Structural integrity
Nuclear Proteins
Glutamine
Proline
Ultracentrifugation
Carrier Proteins
Repair
DNA Repair
RNA
DNA

Cite this

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title = "Crystal structure of a SFPQ/PSPC1 heterodimer provides insights into preferential heterodimerization of human DBHS family proteins",
abstract = "Members of the Drosophila behavior human splicing (DBHS) protein family are nuclear proteins implicated in many layers of nuclear functions, including RNA biogenesis as well as DNA repair. Definitive of the DBHS protein family, the conserved DBHS domain provides a dimerization platform that is critical for the structural integrity and function of these proteins. The three human DBHS proteins, splicing factor proline- and glutamine-rich (SFPQ), paraspeckle component 1 (PSPC1), and non-POU domain-containing octamer-binding protein (NONO), form either homo- or heterodimers; however, the relative affinity and mechanistic details of preferential heterodimerization are yet to be deciphered. Here we report the crystal structure of a SFPQ/PSPC1 heterodimer to 2.3-{\AA} resolution and analyzed the subtle structural differences between the SFPQ/PSPC1 heterodimer and the previously characterized SFPQ homodimer. Analytical ultracentrifugation to estimate the dimerization equilibrium of the SFPQ-containing dimers revealed that the SFPQ-containing dimers dissociate at low micromolar concentrations and that the heterodimers have higher affinities than the homodimer. Moreover, we observed that the apparent dissociation constant for the SFPQ/PSPC1 heterodimer was over 6-fold lower than that of the SFPQ/NONO heterodimer. We propose that these differences in dimerization affinity may represent a potential mechanism by which PSPC1 at a lower relative cellular abundance can outcompete NONO to heterodimerize with SFPQ.",
author = "Jie Huang and {Casas Garcia}, {G Patricia} and Perugini, {Matthew A} and Fox, {Archa H} and Bond, {Charles S} and Mihwa Lee",
note = "{\circledC} 2018 by The American Society for Biochemistry and Molecular Biology, Inc.",
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Crystal structure of a SFPQ/PSPC1 heterodimer provides insights into preferential heterodimerization of human DBHS family proteins. / Huang, Jie; Casas Garcia, G Patricia; Perugini, Matthew A; Fox, Archa H; Bond, Charles S; Lee, Mihwa.

In: The Journal of Biological Chemistry, Vol. 293, No. 17, 27.04.2018, p. 6593-6602.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Crystal structure of a SFPQ/PSPC1 heterodimer provides insights into preferential heterodimerization of human DBHS family proteins

AU - Huang,Jie

AU - Casas Garcia,G Patricia

AU - Perugini,Matthew A

AU - Fox,Archa H

AU - Bond,Charles S

AU - Lee,Mihwa

N1 - © 2018 by The American Society for Biochemistry and Molecular Biology, Inc.

PY - 2018/4/27

Y1 - 2018/4/27

N2 - Members of the Drosophila behavior human splicing (DBHS) protein family are nuclear proteins implicated in many layers of nuclear functions, including RNA biogenesis as well as DNA repair. Definitive of the DBHS protein family, the conserved DBHS domain provides a dimerization platform that is critical for the structural integrity and function of these proteins. The three human DBHS proteins, splicing factor proline- and glutamine-rich (SFPQ), paraspeckle component 1 (PSPC1), and non-POU domain-containing octamer-binding protein (NONO), form either homo- or heterodimers; however, the relative affinity and mechanistic details of preferential heterodimerization are yet to be deciphered. Here we report the crystal structure of a SFPQ/PSPC1 heterodimer to 2.3-Å resolution and analyzed the subtle structural differences between the SFPQ/PSPC1 heterodimer and the previously characterized SFPQ homodimer. Analytical ultracentrifugation to estimate the dimerization equilibrium of the SFPQ-containing dimers revealed that the SFPQ-containing dimers dissociate at low micromolar concentrations and that the heterodimers have higher affinities than the homodimer. Moreover, we observed that the apparent dissociation constant for the SFPQ/PSPC1 heterodimer was over 6-fold lower than that of the SFPQ/NONO heterodimer. We propose that these differences in dimerization affinity may represent a potential mechanism by which PSPC1 at a lower relative cellular abundance can outcompete NONO to heterodimerize with SFPQ.

AB - Members of the Drosophila behavior human splicing (DBHS) protein family are nuclear proteins implicated in many layers of nuclear functions, including RNA biogenesis as well as DNA repair. Definitive of the DBHS protein family, the conserved DBHS domain provides a dimerization platform that is critical for the structural integrity and function of these proteins. The three human DBHS proteins, splicing factor proline- and glutamine-rich (SFPQ), paraspeckle component 1 (PSPC1), and non-POU domain-containing octamer-binding protein (NONO), form either homo- or heterodimers; however, the relative affinity and mechanistic details of preferential heterodimerization are yet to be deciphered. Here we report the crystal structure of a SFPQ/PSPC1 heterodimer to 2.3-Å resolution and analyzed the subtle structural differences between the SFPQ/PSPC1 heterodimer and the previously characterized SFPQ homodimer. Analytical ultracentrifugation to estimate the dimerization equilibrium of the SFPQ-containing dimers revealed that the SFPQ-containing dimers dissociate at low micromolar concentrations and that the heterodimers have higher affinities than the homodimer. Moreover, we observed that the apparent dissociation constant for the SFPQ/PSPC1 heterodimer was over 6-fold lower than that of the SFPQ/NONO heterodimer. We propose that these differences in dimerization affinity may represent a potential mechanism by which PSPC1 at a lower relative cellular abundance can outcompete NONO to heterodimerize with SFPQ.

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DO - 10.1074/jbc.RA117.001451

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SP - 6593

EP - 6602

JO - The Journal of Biological Chemistry

T2 - The Journal of Biological Chemistry

JF - The Journal of Biological Chemistry

SN - 0021-9258

IS - 17

ER -