Analysis of subcellular [57Co] cobalamin distribution in SH-SY5Y neurons and brain tissue

- Methods were developed that can be used to accurately measure [57Co] Cbl levels in lysosomes, mitochondria and cytosol obtained from neuronal and fibroblast cell lines and mouse brain tissue.
- The relative distribution of [57Co] Cbl in neurons and fibroblasts was 6% in the lysosomes, 14% in the mitochondria and 80% in the cytosol.
- This technique was also used to fractionate organelles obtained from mouse brain, and the relative distribution of [57Co] Cbl was 12% in the lysosomes, 15% in the mitochondria and 73% in the cytosol.
- The establishment of subcellular fractionation methods herein provides a useful tool for the investigation of intracellular Cbl trafficking. This method can be adapted to study the effects of age- or neuropathology-related lysosomal dysfunction on intracellular [57Co] Cbl transport in cells and animal brain tissues.