B. Yang et al., HETEROGENEITY OF THE 59-KDA DYSTROPHIN-ASSOCIATED PROTEIN REVEALED BYCDNA CLONING AND EXPRESSION, The Journal of biological chemistry, 269(8), 1994, pp. 6040-6044
The 59-kDa dystrophin-associated protein triplet (59-DAP) is a compone
nt of the dystrophin-glycoprotein complex which may directly associate
with dystrophin. The cDNA encoding one component (59-1 DAP) of the 59
-DAP triplet has now been cloned from rabbit skeletal muscle. The dedu
ced amino acid sequence of 59-1 DAP predicts a 505-amino acid polypept
ide containing nine potential phosphorylation sites and no predicted t
ransmembrane domains. This is consistent with the 59-1 DAP being a per
ipheral membrane protein associated with the cytoplasmic face of the d
ystrophin-glycoprotein complex. Affinity-purified antibodies against r
abbit 59-1 DAP fusion proteins only recognize the lowest band of the 5
9-DAP triplet in skeletal muscle sarcolemma and isolated dystrophin-gl
ycopratein complex. The tissue-specific expression of 59-1 DAP mRNA, w
hich is most prominent in skeletal and cardiac muscle and is also dete
cted in brain, parallels that of dystrophin but not of utrophin. Level
s of 59-1 DAP mRNA are unaffected in mdx mouse skeletal and cardiac mu
scles, although all dystrophin-associated proteins, including 59-DAP,
are greatly reduced in mdx mouse skeletal muscle. However, in mdx mous
e cardiac muscle, the up-regulation of utrophin preserves all dystroph
in-associated proteins except 59-DAP. Our results suggest that the 59-
DAP triplet may contain different protein species and that the 59-1 DA
P may associate more specifically with dystrophin than with utrophin.