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A novel choline cotransporter sequestration compartment in cholinergic neurons revealed by selective endosomal ablation
Author(s) -
Ivy Michael T.,
Newkirk Robert F.,
Wang Yilun,
Townsel James G.
Publication year - 2010
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.2009.06543.x
Subject(s) - endosome , microbiology and biotechnology , horseradish peroxidase , chemistry , endocytosis , choline , cotransporter , biochemistry , intracellular , biology , receptor , sodium , enzyme , organic chemistry
J. Neurochem. (2010) 112 , 1295–1304. Abstract The sodium‐dependent, high affinity choline transporter – choline cotransporter – (ChCoT, aka: cho‐1, CHT1, CHT) undergoes constitutive and regulated trafficking between the plasma membrane and cytoplasmic compartments. The pathways and regulatory mechanisms of this trafficking are not well understood. We report herein studies involving selective endosomal ablation to further our understanding of the trafficking of the ChCoT. Selective ablation of early sorting and recycling endosomes resulted in a decrease of ∼75% of [ 3 H]choline uptake and ∼70% of [ 3 H]hemicholinium‐3 binding. Western blot analysis showed that ablation produced a similar decrease in ChCoTs in the plasma membrane subcellular fraction. The time frame for this loss was approximately 2 h which has been shown to be the constitutive cycling time for ChCoTs in this tissue. Ablation appears to be dependent on the intracellular cycling of transferrin‐conjugated horseradish peroxidase and the selective deposition of transferrin‐conjugated horseradish peroxidase in early endosomes, both sorting and recycling. Ablated brain slices retained their capacity to recruit via regulated trafficking ChCoTs to the plasma membrane. This recruitment of ChCoTs suggests that the recruitable compartment is distinct from the early endosomes. It will be necessary to do further studies to identify the novel sequestration compartment supportive of the ChCoT regulated trafficking.