Poster Presentation The 42nd Lorne Conference on Protein Structure and Function 2017

Characterising coiled-coil mediated functional aggregation in SFPQ (#165)

Jia Ying Lai 1 , Gavin Knott 1 , Amanda Blythe 1 , Archa Fox 2 , Mihwa Lee 3 , Jason Schmidberger 1 , Charlie Bond 1
  1. School of Chemistry and Biochemistry , The University of Western Australia, Perth, Western Australia, Australia
  2. School of Anatomy, Physiology and Human Biology , The University of Western Australia, Perth, Western Australia, Australia
  3. LIMS Institute, La Trobe University , Perth, Western Australia, Australia

Splicing factor proline/glutamine rich (SFPQ) is a multifunctional protein that has been implicated in neuronal pathways [1, 2] in a variety of species, and may be a novel candidate protein that causes amyotrophic lateral sclerosis (ALS). SFPQ is a member of the Drosophila behaviour/human splicing (DBHS) protein family essential for complex gene regulation and mammalian paraspeckle assembly [3]. Paraspeckles are subnuclear bodies composed of the long non-coding RNA, NEAT1 and various paraspeckle proteins including SFPQ [4].

There has already been a well characterised coiled-coil interaction that occurs between amino acids 528-553 of SFPQ monomers [3], however recent evidence suggests that there may be other interactions that occur C terminal to this canonical coiled-coil interaction site.  Here we explore the different types of interactions that can occur between two coiled-coil interaction motifs of SFPQ that is important for functional aggregation and the formation of paraspeckles. Using Small Angle X-Ray Scattering (SAXS) data, we have generated models that describe the different conformations that interacting SFPQ molecules can possess.

We also investigated the effect that DNA would have on the coiled-coil interaction between SFPQ molecules.  SAXS experiments were performed with SFPQ and a 61bp DNA oligonucleotide of the GAGE6 gene promoter region to determine if DNA bound SFPQ changes the amino acid interactions that occur within the coiled-coil interaction motif between two SFPQ molecules.

  1. Lowery, L.A., J. Rubin, and H. Sive, whitesnake/sfpq is required for cell survival and neuronal development in the zebrafish. Developmental Dynamics, 2007. 236(5): p. 1347-1357.
  2. Rendahl, K.G., et al., Defects in courtship and vision caused by amino acid substitutions in a putative RNA-binding protein encoded by the no-on-transient A (nonA) gene of Drosophila. J Neurosci, 1996. 16(4): p. 1511-22.
  3. Lee, M., et al., The structure of human SFPQ reveals a coiled-coil mediated polymer essential for functional aggregation in gene regulation. Nucleic Acids Research, 2015.
  4. Fox, A.H. and A.I. Lamond, Paraspeckles. Cold Spring Harbor Perspectives in Biology, 2010. 2(7): p. a000687.