Si K, Choi YB, White-Grindley E, Majumdar A, Kandel ER.
Aplysia CPEB can form prion-like multimers in sensory neurons that contribute to long-term facilitation.
Cell. 2010 Feb 5;140(3):421-35.
PubMed.
This is a fascinating example of what appears to be another "functional amyloid." In this , the function is more active and interesting because it is regulated by neuronal activity, rather than serving as a scaffold for melanin, or as a storage form for pituitary peptide hormones. It seems likely that it is regulated by a conformation change in the non-prion domain of CPEB in response to 5-HT. The properties of prions may be relevant to learning and memory: they are stable and "self sustaining," at least as long as their assembly from CPEB monomer balances their disassembly by chaperones or their degradation. Another potential property that may be important is their ability to replicate or divide, which might serve to amplify their activity. Prions also are transmissible, which raises the question of whether the CPEB prions are transmitted between neurons, as has been suggested for polyQ peptides, α-synuclein, and tau amyloid oligomers. I think it is likely that most amyloids have prion-like properties such as replication and transmission, but the difference may be that CPEB has been selected by evolution to do this in a highly regulated fashion, which is why it may be functional while the same properties in unregulated amyloids, such as Aβ, may be pathological. What the functional activity consequences of CPEB oligomerization are will be an interesting question.
Comments
University of California, Irvine
This is a fascinating example of what appears to be another "functional amyloid." In this , the function is more active and interesting because it is regulated by neuronal activity, rather than serving as a scaffold for melanin, or as a storage form for pituitary peptide hormones. It seems likely that it is regulated by a conformation change in the non-prion domain of CPEB in response to 5-HT. The properties of prions may be relevant to learning and memory: they are stable and "self sustaining," at least as long as their assembly from CPEB monomer balances their disassembly by chaperones or their degradation. Another potential property that may be important is their ability to replicate or divide, which might serve to amplify their activity. Prions also are transmissible, which raises the question of whether the CPEB prions are transmitted between neurons, as has been suggested for polyQ peptides, α-synuclein, and tau amyloid oligomers. I think it is likely that most amyloids have prion-like properties such as replication and transmission, but the difference may be that CPEB has been selected by evolution to do this in a highly regulated fashion, which is why it may be functional while the same properties in unregulated amyloids, such as Aβ, may be pathological. What the functional activity consequences of CPEB oligomerization are will be an interesting question.
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