Lamins, the major cytoskeleton component of animal nuclei, are nuclear intermediate filament (IF) proteins. They assemble to fibrous structures that are positioned between the inner nuclear membrane and the peripheral chromatin. The organization of the lamin network in somatic cells is still elusive. A small fraction of lamins is also present in the nucleoplasm. Lamins are required for the maintenance of cell shape and nuclear structure. Together with their associated protein partners, they are also required for many essential nuclear functions including DNA replication, RNA Pol II-dependent transcription, nuclear migration and anchorage, correct spacing of nuclear pore complexes, regulation of mitosis, and apoptosis. In the past 20 years an increasing number of mutations in lamins and lamin binding proteins are linked to at least 16 different diseases, called laminopathies. With currently over 450 reported mutations and at least 14 diseases, LMNA is the most frequently mutated among the disease-associated genes. LMNA mutations are implicated in multiple overlapping clinical phenotypes of four major disease types: Striated muscle diseases, lipodystrophic syndromes, peripheral neuropathy and accelerated ageing disorders. A majority of the disease-linked LMNA mutations are autosomal dominant missense mutations scattered throughout the gene that generates aberrant lamin A/C proteins. These mutations may interfere with the folding, stability and assembly of the lamin polypeptide. Lamin mutations may also affect the biochemical properties of the protein, thus affecting lamin A/C interactions with other proteins and possibly also with chromatin. Determining the structure of lamins and studying their roles in mechano-transduction, nuclear organization and metabolism poses a big challenge.
Our current research aims at addressing these challenges. We are currently developing and using novel structural, genetic, cell biology and genomics approaches and state of the are equipment to uncover the structure of lamins and the pathways that they regulate. We have also established laminopathies models in C. elegans and use them to study why different mutations cause the different diseases. We hope that these joint efforts will generate an integrated view of the biology of lamins and their associated proteins.