SYMPOSIUM – LAMINOPATHIES. Characteristics of nuclear proteins and their association with the laminopathies
Irena Niebrój-Dobosz
Genetic studies have now shown that mutations in lamins A/C are present in a heterogenous group of diseases in which they are leading to defects in skeletal muscles, heart, nervous system, fat, skin and bones. The mechanisms leading to the development of laminopathies and the marked differences in phenotypes in the particular laminopathies are not solved, yet. For better understanding the mechanism(s) of laminopathies the localization and structure of lamins, and also the connected with them other nuclear proteins, their synthesis and degradation, their molecular properties, their interactions and probable functions are presented. The lamins, classified already as lamins type A (coded by LMNA gene) and lamins type B (coded by LMN1 and LMN2 genes), are the best characterized nuclear proteins. The structure of other nuclear proteins and their dependence from lamins are still not well defined. The possible mechanism of dilated cardiomyopathy in some laminopathies is also discussed. It is possible that one of the factors responsible for it is an increased susceptibility of cardiomyocytes to mechanical stress because of lamins mutations. Cardiomyopathy may also appear as the consequence of lost nuclei stability in the presence of mutated lamins. The other mechanism may be also the fact that mutated lamins provoke autoimmunologic reactions, cytotoxic against cardiomyocytes.