Review

Acta Neuropathologica

, Volume 125, Issue 6, pp 777-794

Open Access This content is freely available online to anyone, anywhere at any time.

Protein aggregation in amyotrophic lateral sclerosis

  • Anna M. BlokhuisAffiliated withDepartment of Neuroscience and Pharmacology, Rudolf Magnus Institute of Neuroscience, University Medical Center
  • , Ewout J. N. GroenAffiliated withDepartment of Neuroscience and Pharmacology, Rudolf Magnus Institute of Neuroscience, University Medical CenterDepartment of Neurology and Neurosurgery, Rudolf Magnus Institute of Neuroscience, University Medical Center
  • , Max KoppersAffiliated withDepartment of Neuroscience and Pharmacology, Rudolf Magnus Institute of Neuroscience, University Medical CenterDepartment of Neurology and Neurosurgery, Rudolf Magnus Institute of Neuroscience, University Medical Center
  • , Leonard H. van den BergAffiliated withDepartment of Neurology and Neurosurgery, Rudolf Magnus Institute of Neuroscience, University Medical Center
  • , R. Jeroen PasterkampAffiliated withDepartment of Neuroscience and Pharmacology, Rudolf Magnus Institute of Neuroscience, University Medical Center Email author 

Abstract

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease characterized by the aggregation of ubiquitinated proteins in affected motor neurons. Recent studies have identified several new molecular constituents of ALS-linked cellular aggregates, including FUS, TDP-43, OPTN, UBQLN2 and the translational product of intronic repeats in the gene C9ORF72. Mutations in the genes encoding these proteins are found in a subgroup of ALS patients and segregate with disease in familial cases, indicating a causal relationship with disease pathogenesis. Furthermore, these proteins are often detected in aggregates of non-mutation carriers and those observed in other neurodegenerative disorders, supporting a widespread role in neuronal degeneration. The molecular characteristics and distribution of different types of protein aggregates in ALS can be linked to specific genetic alterations and shows a remarkable overlap hinting at a convergence of underlying cellular processes and pathological effects. Thus far, self-aggregating properties of prion-like domains, altered RNA granule formation and dysfunction of the protein quality control system have been suggested to contribute to protein aggregation in ALS. The precise pathological effects of protein aggregation remain largely unknown, but experimental evidence hints at both gain- and loss-of-function mechanisms. Here, we discuss recent advances in our understanding of the molecular make-up, formation, and mechanism-of-action of protein aggregates in ALS. Further insight into protein aggregation will not only deepen our understanding of ALS pathogenesis but also may provide novel avenues for therapeutic intervention.

Keywords

Amyotrophic lateral sclerosis (ALS) Aggregation Protein degradation Motor neuron RNA granule