Arc self‐association and formation of virus‐like capsids are mediated by an N‐terminal helical coil motif

DOI: 10.1111/febs.15618

Authors: Maria S. Eriksen (University of Bergen;) , Oleksii Nikolaienko (University of Bergen) , Erik I. Hallin (University of Bergen) , Sverre Grødem (University of Bergen) , Helene J. Bustad (University of Bergen) , Marte I. Flydal (University of Bergen) , Ian Merski (University of Massachusetts Amherst) , Tomohisa Hosokawa (Kyoto University Graduate School of Medicine) , Daniela Lascu (University of Bergen) , Shreeram Akerkar (University of Bergen) , Jorge Cuellar (Centro Nacional de Biotecnología (CNB‐CSIC)) , James J. Chambers (University of Massachusetts Amherst) , Rory O’connell (University of Massachusetts Amherst) , Gopinath Muruganandam (VIB‐VUB Center for Structural Biology; Vrije Universiteit Brussel) , Remy Loris (VIB‐VUB Center for Structural Biology; Vrije Universiteit Brussel) , Christine Touma (University of Oulu) , Tambudzai Kanhema (University of Bergen) , Yasunori Hayashi (Kyoto University Graduate School of Medicine) , Margaret M. Stratton (University of Massachusetts Amherst) , José M. Valpuesta (Centro Nacional de Biotecnología (CNB‐CSIC)) , Petri Kursula (University of Bergen; University of Oulu) , Aurora Martinez (University of Bergen) , Clive R. Bramham (University of Bergen)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: The Febs Journal , VOL 3

State: Published (Approved)
Published: November 2020

Abstract: Activity‐regulated cytoskeleton‐associated protein (Arc) is a protein interaction hub with diverse roles in intracellular neuronal signaling, and important functions in neuronal synaptic plasticity, memory, and postnatal cortical development. Arc has homology to retroviral Gag protein and is capable of self‐assembly into virus‐like capsids implicated in the intercellular transfer of RNA. However, the molecular basis of Arc self‐association and capsid formation is largely unknown. Here, we identified a 28‐amino‐acid stretch in the mammalian Arc N‐terminal (NT) domain that is necessary and sufficient for self‐association. Within this region, we identified a 7‐residue oligomerization motif, critical for the formation of virus‐like capsids. Purified wild‐type Arc formed capsids as shown by transmission and cryo‐electron microscopy, whereas mutant Arc with disruption of the oligomerization motif formed homogenous dimers. An atomic‐resolution crystal structure of the oligomerization region peptide demonstrated an antiparallel coiled‐coil interface, strongly supporting NT‐NT domain interactions in Arc oligomerization. The NT coil–coil interaction was also validated in live neurons using fluorescence lifetime FRET imaging, and mutation of the oligomerization motif disrupted Arc‐facilitated endocytosis. Furthermore, using single‐molecule photobleaching, we show that Arc mRNA greatly enhances higher‐order oligomerization in a manner dependent on the oligomerization motif. In conclusion, a helical coil in the Arc NT domain supports self‐association above the dimer stage, mRNA‐induced oligomerization, and formation of virus‐like capsids.

Journal Keywords: activity‐regulated cytoskeleton‐associated protein (Arc)/coiled‐coil interactions/protein oligomerization; retrovirus‐like capsid/synaptic plasticity

Subject Areas: Biology and Bio-materials, Chemistry


Instruments: B21-High Throughput SAXS

Other Facilities: P13 at PETRA III; SWING at SOLEIL

Added On: 19/04/2021 22:01

Discipline Tags:

Biochemistry Genetics Chemistry Structural biology Life Sciences & Biotech

Technical Tags:

Scattering Small Angle X-ray Scattering (SAXS)