L. Carlsson et al., Differences in the distribution of synemin, paranemin, and plectin in skeletal muscles of wild-type and desmin knock-out mice, HISTOCHEM C, 114(1), 2000, pp. 39-47
Mice lacking the gene encoding fur the intermediate filament protein desmin
have a surprisingly normal myofibrillar organization in skeletal muscle fi
bers, although myopathy develops in highly used muscles. In the present stu
dy we examined how synemin, paranemin, and plectin, three key cytoskeletal
proteins related to desmin, are organized in normal and desmin knock-out (K
/O) mice. We show that in wild-type mice, synemin, paranemin, and plectin w
ere colocalized with desmin in Z-disc-associated striations and at the sarc
olemma. All three proteins were also present at the myotendinous junctions
and in the postsynaptic area of motor end-plates. In the desmin K/O mice th
e distribution of plectin was unaffected, whereas synemin and paranemin wer
e partly affected. The Z-disc-associated striations were in general no long
er present in between the myofibrils. In contrast, at the myotendinous and
neuromuscular junctions synemin and paranemin were still present. Our study
shows that plectin differs from synemin and paranemin in its binding prope
rties to the myofibrillar Z-discs and that the cytoskeleton in junctional a
reas is particularly complex in its organization.