ISSN:
1573-4919
Keywords:
neonatal rat brains
;
MAPs
;
polyaspartic acid
;
MAP-3
;
interaction with calmodulin
;
C-terminal tubulin peptides
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Chemistry and Pharmacology
,
Medicine
Notes:
Abstract The changes in the levels of microtubule-associated proteins (MAPs) during advanced embryonic stages, neonatal and adult organisms reflect the importance of these cytoskeletal proteins in relation to the morphogenesis of the central nervous system. MAP-1B is found in prenatal brains and it appears to have the highests levels in neonatal rat brains, being a developmentally-regulated protein. In this research, a fast procedure to isolate MAP-1B, as well as MAP-2 and MAP-3 from neonatal rat brains was designed, based on the differential capacity of poly L-aspartic acid to release MAPs during temperature-dependent cycles of microtubule assembly in the absence of taxol. The high molecular weight MAP-1B was recovered in the warm supernatants after microtubular protein polymerization in the presence of low concentrations of polyaspartic acid. Instead, MAP-2 and a 180 kDa protein with characteristics of MAP-3 remained associated to the polymer after the assembly. Further purification of MAP-1B was attained after phosphocellulose chromatography. Isolation of MAP-2 isoforms together with MAP-3 was achieved on the basis of their selective interactions with calmodulin-agarose affinity columns. In addition, MAP-2 and MAP-3 were also purified on the basis of their capacities to interact with the tubulin peptide β-II (422–434) derivatized on an Affigel matrix. However, MAP-1B did not interact with the β-II tubulin fragment, but it showed interaction with the Affigel-conjugated β-I (431–444) tubulin peptide. The different MAPs componentes were characterized by western blots using specific monoclonal antibodies. A salient feature of neonatal rat brain MAP-3 was its interactions with site-directed antibodies that recognize binding epitopes on the repetitive sequences of tau and MAP-2. However, these site-specific antibodies did not interact with MAP-1B from the neonatal rat brain tissue.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00925946
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