Journal of Neuroscience, Vol 10, 3344-3352, Copyright © 1990 by Society for Neuroscience
The cold stability of microtubules increases during axonal maturation
DF Watson, PN Hoffman and JW Griffin
Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205.
The development of cold-stable microtubules (MTs) was studied in maturing
rat sciatic nerves. From 4 to 10 weeks of age, there was a large increase
in the proportion of tubulin associated with stable MTs. A greater fraction
of axonal tubulin than nonaxonal tubulin was associated with stable MTs.
The labeled tubulin remaining behind the peak of slow axonal transport was
more highly associated with stable MTs than tubulin in the peak itself.
Immunoassay confirmed that the sciatic nerve contains a pool of stable MTs
not identical to the peak of tubulin transport. The developmental increase
in MT stability is not associated with any increase in the acetylation of
tubulin or with alterations in the major MT-associated proteins. One aspect
of maturation of the axonal cytoskeleton may involve deposition of tubulin
into stable MTs that are either stationary or moving slowly with regard to
the peak of transported tubulin.