Huntingtin is a cytoplasmic protein associated with vesicles in human and rat brain neurons

M DiFiglia, E Sapp, K Chase, C Schwarz, A Meloni… - Neuron, 1995 - cell.com
M DiFiglia, E Sapp, K Chase, C Schwarz, A Meloni, C Young, E Martin, JP Vonsattel…
Neuron, 1995cell.com
The gene defective in Huntington's disease encodes a protein, huntingtin, with unknown
function. Antisera generated against three separate regions of huntingtin identified a single
high molecular weight protein of 320 kDa on immunoblots of human neuroblastoma extracts.
The same protein species was detected in human and rat cortex synaptosomes and in
sucrose density gradients of vesicle-enriched fractions, where huntingtin immunoreacUvity
overlapped with the distribution of vesicle membrane proteins (SV2, transferrin receptor, and …
Summary
The gene defective in Huntington's disease encodes a protein, huntingtin, with unknown function. Antisera generated against three separate regions of huntingtin identified a single high molecular weight protein of 320 kDa on immunoblots of human neuroblastoma extracts. The same protein species was detected in human and rat cortex synaptosomes and in sucrose density gradients of vesicle-enriched fractions, where huntingtin immunoreacUvity overlapped with the distribution of vesicle membrane proteins (SV2, transferrin receptor, and synaptophysin). Immunohistochemistry in human and rat brain revealed widespread cytoplasmic labeling of huntingtin within neurons, particularly cell bodies and dendrites, rather than the more selective pattern of axon terminal labeling characteristic of many vesicle-associated proteins. At the ultrastructural level, immunoreacUvity in cortical neurons was detected in the matrix of the cytoplasm and around the membranes of the vesicles. The ubiquitous cytoplasmic distribution of huntingtin in neurons and its association with vesicles suggest that huntingtin may have a role in vesicle trafficking.
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