Lamins are components of the nuclear lamina, a fibrous layer on the nucleoplasmic side of the inner nuclear membrane, which is thought to provide a framework for the nuclear envelope and may also interact with chromatin. Lamin A and C are present in equal amounts in the lamina of mammals. Recruited by DNA repair proteins XRCC4 and IFFO1 to the DNA double-strand breaks (DSBs) to prevent chromosome translocation by immobilizing broken DNA ends (By similarity). Plays an important role in nuclear assembly, chromatin organization, nuclear membrane and telomere dynamics. Required for normal development of peripheral nervous system and skeletal muscle and for muscle satellite cell proliferation. Required for osteoblastogenesis and bone formation. Also prevents fat infiltration of muscle and bone marrow, helping to maintain the volume and strength of skeletal muscle and bone. Required for cardiac homeostasis (PubMed:26436652). Isoform C2 may have a role in determining the organization of nuclear and chromosomal structures during spermatogenesis. Prelamin-A/C can accelerate smooth muscle cell senescence. It acts to disrupt mitosis and induce DNA damage in vascular smooth muscle cells (VSMCs), leading to mitotic failure, genomic instability, and premature senescence (By similarity). Homodimer of lamin A and lamin C. Interacts with lamin-associated polypeptides IA, IB and TMPO-alpha, RB1 and with emerin. Proteolytically processed isoform A interacts with NARF (By similarity). Interacts with SREBF1, SREBF2, SUN1, SUN2 and TMEM43. Interacts with TMEM201. Prelamin-A/C interacts with EMD. Interacts with DMPK; may regulate nuclear envelope stability (By similarity). Interacts with MLIP (PubMed:26436652, PubMed:21498514). Interacts with SUV39H1; the interaction increases stability of SUV39H1. Interacts with ITSN1 isoform 2 (By similarity). Interacts with IFFO1; the interaction forms an interior nucleoskeleton and the recruitment to DNA double-strand breaks (By similarity). Interacts (via C-terminus) with LEMD2 (via N-terminus) (in vitro). Farnesylation of prelamin-A/C facilitates nuclear envelope targeting and subsequent cleavage by ZMPSTE24/FACE1 to remove the farnesyl group produces mature lamin-A/C, which can then be inserted into the nuclear lamina. EMD is required for proper localization of non-farnesylated prelamin-A/C (By similarity). Isoform A and isoform C are present in equal amounts in the lamina of mammals. Expressed in liver and in bone marrow (at protein level). Isoform C2 is specifically expressed in germ cells. Expressed in cardiomyocytes (PubMed:26436652). Proteolytic cleavage of the C-terminal of 18 residues of prelamin-A/C results in the production of lamin-A/C. The prelamin-A/C maturation pathway includes farnesylation of CAAX motif, ZMPSTE24/FACE1 mediated cleavage of the last three amino acids, methylation of the C-terminal cysteine and endoproteolytic removal of the last 15 C-terminal amino acids. Proteolytic cleavage requires prior farnesylation and methylation, and absence of these blocks cleavage (By similarity). Sumoylation is necessary for the localization to the nuclear envelope. Farnesylation of prelamin-A/C facilitates nuclear envelope targeting. Increased phosphorylation of the lamins occurs before envelope disintegration and probably plays a role in regulating lamin associations. Phosphorylation status of S-22 determines its localization between double-strand break (DSB) sites and the nuclear matrix (By similarity). Isoform C is phosphorylated on Ser-392, Ser-407 and Ser-409 at interphase. The N-terminus is blocked. Mutant mice survive postnatally for 6-8 weeks and show skeletal and cardiac myopathy, sarcopenia, osteopenia, decreased bone formation, neuropathy, abnormal neuromuscular junctions, decreased skeletal muscle growth and decreased muscle satellite cell proliferation. They develop ventricular dilation and cardiac dysfunction. Within 2-3 weeks they show a reduction in their growth rate and by week 4 their growth ceases with their mean body weight being half of that of the wild-type or the heterozygous littermates. Simultaneous knockout of LMNA and LAP2 results in partial rescue of the phenotype, with a 30% increase in survival rate and a 25-50% increase in body weight. Double knockouts for MLIP and LMNA die sooner than single LMNA knockout. They develop much more severe ventricular dilation and cardiac dysfunction (PubMed:26436652). The structural integrity of the lamina is strictly controlled by the cell cycle, as seen by the disintegration and formation of the nuclear envelope in prophase and telophase, respectively. Belongs to the intermediate filament family. Extended N-terminus.