Lamin A/C

Lamin A/C
Name	Lamin A/C
Uniprot	P02545
Type	Intermediate filament protein
Location	Nuclear lamina

Lamin A/C is a pair of nuclear intermediate filament proteins encoded by the human LMNA gene that form a major structural network beneath the inner nuclear membrane and link chromatin to nuclear architecture. They are central to mechanotransduction, chromatin organization, gene regulation, DNA repair, and signaling pathways implicated in aging and tissue-specific diseases. Lamin A/C connects nuclear structure to cellular function across diverse contexts from embryogenesis to adult tissue homeostasis.

Structure and biochemistry

Lamin A/C are type V intermediate filament proteins sharing structural features with other filament proteins studied by researchers at institutions like Max Planck Society and Cold Spring Harbor Laboratory, including a central α-helical rod domain flanked by a head and a tail domain homologous to domains characterized in studies at Harvard University and Stanford University. High-resolution structural work at facilities such as the European Molecular Biology Laboratory and Brookhaven National Laboratory resolved coiled-coil dimerization and higher-order polymerization motifs related to filament assembly phenomena investigated at Massachusetts Institute of Technology and University of Cambridge. The C-terminal tail contains an immunoglobulin-like fold conserved across metazoans and analyzed in comparative studies from University of Tokyo and University of California, Berkeley. Biochemical assays developed at Johns Hopkins University and University of Oxford revealed that lamin polymers form a meshwork interacting with inner nuclear membrane proteins such as emerin and LBR and with chromatin-binding complexes studied at National Institutes of Health and European Research Council-funded labs. Mass spectrometry labs at EMBL and Scripps Research mapped post-translational modification sites central to lamin biochemistry.

Expression, isoforms, and post-translational processing

Expression of LMNA is regulated developmentally and in response to mechanical cues in contexts investigated by teams at University College London and University of Pennsylvania, producing major isoforms Lamin A and Lamin C via alternative splicing, as first characterized in studies from Yale University and Columbia University. Lamin A is translated as prelamin A and undergoes a multistep post-translational processing pathway involving farnesylation, endoproteolytic cleavage by ZMPSTE24 (studied at NIH), methylation, and final cleavage to yield mature lamin A—steps dissected in biochemical work at University of Michigan and University of Chicago. Lamin C lacks the C-terminal CAAX motif and bypasses farnesylation, a distinction clarified in comparative analyses at University of Washington and Duke University. Alternative transcripts, minor splice variants, and cell-type–specific promoter usage were characterized in transcriptomics studies at Broad Institute and European Bioinformatics Institute.

Cellular functions and interactions

Lamin A/C interact with a broad interactome including inner nuclear membrane proteins like emerin and MAN1, chromatin regulators such as HDAC3 and BAF, and transcriptional regulators studied at Max Planck Institute for Molecular Genetics and Cold Spring Harbor Laboratory. Proteomic screens from Wellcome Sanger Institute and Proteomics Facility, Yale mapped connections to DNA repair factors like 53BP1 and RAD51 and to signaling hubs including MAPK and PI3K pathways investigated in laboratories at University of California, San Diego and Imperial College London. Lamin A/C contribute to tethering of lamina-associated domains (LADs) identified in genomic mapping projects at Broad Institute and ENCODE consortium collaborators, impacting transcriptional repression at loci studied by groups at Karolinska Institutet and Institut Pasteur. Mechanotransduction roles were elucidated in biomechanics work at ETH Zurich and University of Cambridge, linking lamin levels to nuclear stiffness measured in microfluidics studies at MIT and Harvard Medical School.

Role in development and tissue-specific biology

LMNA expression dynamics influence processes from early embryogenesis to lineage specification analyzed by developmental labs at Max Planck Institute for Developmental Biology and Salk Institute. Tissue-specific lamin requirements were revealed by mouse models developed at The Jackson Laboratory and conditional knockout strategies at Stanford University School of Medicine, showing critical roles in skeletal muscle, cardiac muscle, adipose tissue, and peripheral nerve biology studied at Mayo Clinic and Cleveland Clinic. Cardiac conduction and structural integrity findings from clinical centers like Mount Sinai Health System and Johns Hopkins Hospital connected lamin dysfunction to cardiomyopathy phenotypes, while adipocyte differentiation and lipodystrophy links emerged from research at University of Texas Southwestern Medical Center and National Heart, Lung, and Blood Institute. Neural crest and craniofacial development effects were examined in studies from University of California, San Francisco.

Disease associations and laminopathies

Mutations in LMNA cause a spectrum of disorders collectively termed laminopathies, first clinically described in cohorts from Mayo Clinic and Cleveland Clinic and extensively cataloged by consortia including ClinVar and OMIM curators. Clinically distinct entities include dilated cardiomyopathy with conduction defects (DCM) observed in patients at Massachusetts General Hospital, Emery–Dreifuss muscular dystrophy cases reported from Johns Hopkins Hospital, familial partial lipodystrophy type 2 (FPLD2) characterized in cohorts at University of Paris and National Institute for Health and Care Research, and Hutchinson–Gilford progeria syndrome (HGPS) first described by teams at Harvard Medical School and Boston Children’s Hospital. Pathological features span cardiac failure, skeletal muscle wasting, metabolic dysregulation, peripheral neuropathy, and premature aging phenotypes studied in clinical trials at NIH Clinical Center and translational programs at Duke University Medical Center.

Molecular mechanisms and pathogenic models

Pathogenic LMNA variants perturb nuclear mechanics, chromatin organization, and signaling pathways; mechanistic models were developed through interdisciplinary collaborations involving Wellcome Trust-funded groups and laboratories at Rockefeller University. Studies using patient-derived fibroblasts and induced pluripotent stem cells from centers such as Stanford Medicine and Broad Institute revealed altered mechanotransduction, defective DNA repair, and misregulated gene expression programs. Mouse and zebrafish models created at European Molecular Biology Laboratory and Weill Cornell Medicine recapitulated tissue-specific phenotypes and informed therapeutic strategies tested in preclinical studies at Biogen, Novartis, and academic translational centers including Massachusetts General Hospital Translational Research Center. Therapeutic approaches targeting farnesylation, proteostasis, and chromatin modifiers progressed through trials at FDA-registered centers and collaborative consortia including researchers from UCLA and University of Pennsylvania.

Category:Nuclear lamina proteins