This domain is found in Activity-regulated cytoskeleton-associated protein from humans (Arc), a master regulator of synaptic plasticity that promotes endocytosis of AMPA receptors and a postsynaptic mediator of activity-dependent synapse elimination in the developing cerebellum. This protein is associated with cognitive diseases. This Gag-like protein has the topology of a retroviral Gag protein, with a central capsid domain (this entry) with two globular subdomains, the N-lobe and the C-lobe, consisting of four and five alpha-helices, connected by a short non-helical segment [1-3].

1: Structural basis of arc binding to synaptic proteins: implications for cognitive disease. Zhang W, Wu J, Ward MD, Yang S, Chuang YA, Xiao M, Li R, Leahy DJ, Worley PF; Neuron. 2015;86:490-500. PMID:25864631

2: The Capsid Domain of Arc Changes Its Oligomerization Propensity through Direct Interaction with the NMDA Receptor. Nielsen LD, Pedersen CP, Erlendsson S, Teilum K; Structure. 2019;27:1071-1081. PMID:31080121

3: Structural properties and peptide ligand binding of the capsid homology domains of human Arc. Hallin EI, Bramham CR, Kursula P; Biochem Biophys Rep. 2021;26:100975. PMID:33732907