Cell biology

Laser scanning cytometry

Laser scanning cytometry (LSC) is a slide-based technique in which lasers scan cells on a microscope slide, producing per-cell fluorescence data comparable to flow cytometry.

LASP1 (LIM and SH3 domain protein 1, formerly MLN50) is a 261-amino-acid human actin-binding phosphoprotein cloned from breast cancer metastases in 1995; it shuttles between focal adhesions and the nucleus and is overexpressed in many cancers.

Lattice light-sheet microscopy

Lattice light-sheet microscopy is a fluorescence microscopy method that images living cells in 3D using an ultrathin light sheet, with far less phototoxicity than confocal microscopy.

Leigh syndrome

Leigh syndrome (subacute necrotizing encephalomyelopathy, Leigh syndrome spectrum) is a progressive mitochondrial neurodegenerative disorder of infancy, affecting over 110 genes, with bilateral brainstem and basal ganglia lesions, lactic acidosis, and death often by age three.

Lethal infantile mitochondrial myopathy

Lethal infantile mitochondrial myopathy (LIMM, LIMD; OMIM 551000) is a rare mtDNA-related oxidative phosphorylation disorder causing neonatal hypotonia, ophthalmoplegia, severe lactic acidosis, and death days to months after birth.

Ligament

Ligament: fibrous connective tissue joining bone to bone, over 900 in the body, mostly type I collagen and elastin; stabilizes joints, heals as inferior scar tissue, often reconstructed by graft (ACL, Tommy John surgery).

Oct 20, 2026

Ligament cell

Ligament cell (ligamentocyte, ligament fibroblast): the principal fibroblast-like cell of ligaments, located between collagen fibrils, quiescent, synthesizing type I/III collagen ECM, communicating via connexin 32/43 gap junction processes.

Ligand-gated ion channel

Ligand-gated ion channels (LGICs, ionotropic receptors): membrane proteins combining a neurotransmitter binding site and an ion pore, mediating millisecond fast synaptic transmission. Families include pentameric Cys-loop (nicotinic ACh, GABAA, glycine, 5-HT3), ionotropic glutamate, and P2X receptors; the nicotinic acetylcholine receptor, isolated in 1970, was the first identified.

Ligand-receptor interactions

Ligand-receptor interactions: specific high-affinity binding of ligands (hormones, drugs, antigens) to receptors (GPCRs, ion channels, kinases, nuclear receptors), the basis of cell signaling, pharmacology, biosensors, and disease mechanisms.

Lineage tracing

Lineage tracing identifies all progeny of a single cell by placing a stable, inherited mark in it. Once an invertebrate embryology technique, it is now central to studying stem cell behavior in adult mammalian tissues.

Lipid bilayer

Lipid bilayer: the ~5 nm double layer of amphipathic phospholipids forming all biological membranes; basis of the fluid mosaic model, lipid rafts, and liposome drug delivery.

Oct 20, 2026

Lipophagy

Lipophagy is the selective autophagic degradation of lipid droplets in lysosomes, discovered in 2009; it fuels mitochondrial β-oxidation, is regulated by AMPK–mTORC1–TFEB, and its dysfunction contributes to fatty liver disease, atherosclerosis, and cancer.

Live cell imaging

Live cell imaging is a microscopy method that records time-lapse images of living cells over minutes to days, following individual cells through division, migration, signaling, and drug response.

Live-cell microscopy

Live-cell microscopy is the time-resolved observation of living, unfixed cells under a microscope, following processes like cell division and migration while keeping light damage low.

LLC-MK2

LLC-MK2 (Lilly Laboratories Culture-Monkey Kidney 2), also written LLCMK2, is a spontaneously immortalized rhesus macaque kidney epithelial cell line established by Hull, Cherry, and Tritch at Lilly Research Laboratories (ATCC CCL-7, Cellosaurus CVCL_3009), widely used for virus isolation including parainfluenza, mumps, metapneumovirus, SARS-CoV, and SARS-CoV-2.

LLC-PK1

LLC-PK1, from Lilly Laboratories Culture-Porcine Kidney 1, is a pig kidney epithelial cell line developed in 1958 and used as a model of the renal proximal tubule.

LN-18

LN-18 (CVCL_0392, ATCC CRL-2610) is a human glioblastoma cell line established in 1976 from a right temporal lobe tumor of a male patient; TP53-mutant, CDKN2A-deleted, PTEN wild-type, temozolomide-resistant, authenticated by STR profiling.

LN-229

LN-229 (CVCL_0393, ATCC CRL-2611) is a human glioblastoma cell line established in 1979 from a 60-year-old female patient; adherent, TP53-mutant, PTEN wild-type, p16/p14ARF-deleted, tumorigenic in nude mice.

LNCaP

LNCaP (Lymph Node Carcinoma of the Prostate) is the most-used human prostate cancer cell line, derived from a lymph node metastasis; androgen-sensitive, AR- and PSA-positive, AR T878A mutant, PTEN-deficient.

Locus coeruleus

Locus coeruleus (blue spot): small pigmented brainstem nucleus in the dorsolateral pons, the brain's principal source of norepinephrine, regulating arousal, sleep–wake cycling, attention, and implicated early in Alzheimer's and Parkinson's pathology.

Long-chain-fatty-acid—CoA ligase

Long-chain-fatty-acid—CoA ligase (ACSL, long-chain acyl-CoA synthetase) activates C12-C20 fatty acids to acyl-CoA via ATP and CoA. Five mammalian isoforms (ACSL1, 3, 4, 5, 6) differ in substrate preference, location, and roles in ferroptosis and cancer.