MABS1215 Sigma-AldrichAnti-Calpain I/II, large subunit Antibody, clone 1D10A7

Lissencephaly is a devastating neurological disorder caused by defective neuronal migration. LIS1 (official symbol PAFAH1B1, for platelet-activating factor acetylhydrolase, isoform 1b, subunit 1) was identified as the gene mutated in individuals with lissencephaly, and it was found to regulate cytoplasmic dynein function and localization. Here we show that inhibition or knockdown of calpains protects LIS1 from proteolysis, resulting in the augmentation of LIS1 amounts in Lis1(+/-) mouse embryonic fibroblast cells and rescue of the aberrant distribution of cytoplasmic dynein, mitochondria and beta-COP-positive vesicles. We also show that calpain inhibitors improve neuronal migration of Lis1(+/-) cerebellar granular neurons. Intraperitoneal injection of the calpain inhibitor ALLN to pregnant Lis1(+/-) dams rescued apoptotic neuronal cell death and neuronal migration defects in Lis1(+/-) offspring. Furthermore, in utero knockdown of calpain by short hairpin RNA rescued defective cortical layering in Lis1(+/-) mice. Thus, calpain inhibition is a potential therapeutic intervention for lissencephaly.

Fifteen hybridomas secreting antibodies against calcium-activated neutral protease (CANP), especially those for rabbit muscle mCANP with low calcium sensitivity, have been produced by the cell fusion technique. Eight of the monoclonal antibodies belong to the class IgG1, one to the class IgG2a, and six to the class IgG2b. The antibodies from these clones were characterized with regard to their relative binding affinities to the large subunits (80K) and the small subunits (30K) of mCANP as well as mu CANP, which is another type of CANP with high calcium sensitivity. Fourteen antibodies bound only to the 80K subunit of mCANP and one antibody bound to the 80K subunit of both mCANP and mu CANP. These antibodies recognized rat mCANP but not chicken CANP, with the exception of one antibody. Examination of the effects of these antibodies on the enzyme activity of mCANP showed that six antibodies partially inhibited the enzyme activity and the others were noninhibitory. These monoclonal antibodies should be useful for analyzing the fine structure of CANPs and the mechanism of the activation of mCANP, and also for determining the intracellular localization of mCANP.