Ubiquitin
is a highly conserved protein of about 8.5 kDa molecular
weight, which has a normal role in the targeting of proteins
for proteolytic degradation. To perform this function,
the protein to be degraded is first covalently attached
to the C-terminus of ubiquitin, and the ubiquitinated complex
is then recognized by a complex of degradative enzymes.
Interestingly, ubiquitin also becomes covalently bonded
to many types of pathological inclusions, which appear
to be resistant to normal degradation. Therefore, ubiquitin
antibodies are very useful for studies of these inclusions.
For example, the neurofibrillary tangles and paired helical
filaments diagnostic of Alzheimer?s disease, Lewy bodies
seen in Parkinson’s disease, and Pick bodies found
in Pick’s disease are all heavily ubiquitinated and
can be readily visualized with ubiquitin antibodies.
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