DEGRADATION OF MICROTUBULE-ASSOCIATED PROTEIN-2 AND BRAIN SPECTRIN BY CALPAIN - A COMPARATIVE-STUDY
DEGRADATION OF MICROTUBULE-ASSOCIATED PROTEIN-2 AND BRAIN SPECTRIN BY CALPAIN - A COMPARATIVE-STUDY
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DOI：
10.1111/j.1471-4159.1991.tb02061.x
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发表时间：
1991-05-01
影响因子：
4.7
通讯作者：
JOPE, RS
中科院分区：
文献类型：
--
作者：
JOHNSON, GVW;LITERSKY, JM;JOPE, RS
The in vitro degradation of microtubule-associated protein 2 (MAP-2) and spectrin by the calcium-dependent neutral protease calpain was studied. Five major results are reported. First, MAP-2 isolated from twice-cycled microtubules (2 X MT MAP-2) was extremely sensitive to calpain-induced hydrolysis. Even at an enzyme-to-substrate ratio (wt/wt) of 1:200, 2 X MT MAP-2 was significantly degraded by calpain. Second, MAP-2 purified from the total brain heat-stable fraction (total MAP-2) was significantly more resistant to calpain-induced hydrolysis compared with 2 X MT MAP-2. Third, MAP-2a and MAP-2b were proteolyzed similarly by calpain, although some relative resistance of MAP-2b was observed. Fourth, the presence of calmodulin significantly increased the extent of calpain-induced hydrolysis of the alpha-subunit of spectrin. Fifth, the two neuronal isoforms of brain spectrin (240/235 and 240/235E, referred to as alpha/beta-N and alpha/beta-E, respectively) showed different sensitivities to calpain. alpha-N-spectrin was significantly more sensitive to calpain-induced degradation compared to alpha-E-spectrin. Among other things, these results suggest a role for the calpain-induced degradation of MAP-2, as well as spectrin, in such physiological processes as alterations in synaptic efficacy, dendritic remodeling, and in pathological processes associated with neurodegeneration.
