Serum cholinesterase activity in infantile and juvenile spinal muscular atrophy

SMN-primed ribosomes modulate the translation of transcripts related to spinal muscular atrophy

The contribution of ribosome heterogeneity and ribosome-associated proteins to the molecular control of proteomes in health and disease remains unclear. Here, we demonstrate that survival motor neuron (SMN) protein-the loss of which causes the neuromuscular disease spinal muscular atrophy (SMA)-binds to ribosomes and that this interaction is tissue-dependent. SMN-primed ribosomes are preferentially positioned within the first five codons of a set of mRNAs that are enriched for translational enhancer sequences in the 5' untranslated region (UTR) and rare codons at the beginning of their coding sequence. These SMN-specific mRNAs are associated with neurogenesis, lipid metabolism, ubiquitination, chromatin regulation and translation. Loss of SMN induces ribosome depletion, especially at the beginning of the coding sequence of SMN-specific mRNAs, leading to impairment of proteins that are involved in motor neuron function and stability, including acetylcholinesterase. Thus, SMN plays a crucial role in the regulation of ribosome fluxes along mRNAs encoding proteins that are relevant to SMA pathogenesis.

Plasma and serum G4 isoenzyme of acetylcholinesterase in patients with Alzheimer-type dementia and vascular dementia

We developed a new assay for plasma or serum G4 acetylcholinesterase (AChE) activity. There was no difference in G4 AChE activity between serum and plasma. Plasma AChE activity in control subjects (8-92 years) was independent of age. Serum G4 AChE activity was significantly increased in patients with vascular dementia (P less than 0.01), compared with age-matched control, and significantly decreased in those with probable Alzheimer-type dementia (P less than 0.02). The difference between VD and ATD was significant (P less than 0.001), and thus the measurement of plasma or serum G4 AChE activity would be helpful in the differential diagnosis of dementia.