Lamins are the major architectural proteins of the nucleus and are essential for nuclear integrity and assembly. Lamins are also involved in the organization of nuclear functions such as DNA replication, transcription, and repair. Mutations in the human lamin genes lead to highly debilitating genetic diseases that affect a number of different tissues such as muscle, adipose, and neuronal tissues, or cause premature aging syndromes. The observed interactions of lamins with inner nuclear membrane proteins, chromatin, and various regulatory factors have given important insights into the role of lamins in cellular processes and tissue-specific signaling pathways.