Lymphotoxin beta

Lymphotoxin-beta (LT-beta) formerly known as tumor necrosis factor C (TNF-C) is a protein that in humans is encoded by the LTB gene.^[5][6][7]

LTB
Available structures PDB Ortholog search: PDBe RCSB List of PDB id codes 4MXW
Identifiers
Aliases	LTB, TNFC, TNFSF3, p33, Lymphotoxin beta, TNLG1C
External IDs	OMIM: 600978; MGI: 104796; HomoloGene: 1752; GeneCards: LTB; OMA:LTB - orthologs
Gene location (Human) Chr. Chromosome 6 (human)[1] Band 6p21.33 Start 31,580,525 bp[1] End 31,582,522 bp[1]
Gene location (Mouse) Chr. Chromosome 17 (mouse)[2] Band 17 B1|17 18.59 cM Start 35,413,415 bp[2] End 35,415,296 bp[2]
RNA expression pattern Bgee Human Mouse (ortholog) Top expressed in granulocyte spleen lymph node blood appendix mucosa of transverse colon monocyte testicle bone marrow bone marrow cell Top expressed in spleen granulocyte thymus bone marrow white pulp embryo jejunum colon ileum embryo More reference expression data BioGPS More reference expression data
Gene ontology Molecular function tumor necrosis factor receptor binding cytokine activity signaling receptor binding Cellular component integral component of membrane plasma membrane membrane extracellular space cellular component Biological process cell-cell signaling tumor necrosis factor-mediated signaling pathway lymph node development gene expression immune response signal transduction skin development regulation of signaling receptor activity Sources:Amigo / QuickGO
Orthologs Species Human Mouse Entrez 4050 16994 Ensembl ENSG00000223448 ENSG00000238114 ENSG00000236925 ENSG00000231314 ENSG00000204487 ENSG00000236237 ENSG00000227507 ENSG00000206437 ENSMUSG00000024399 UniProt Q06643 P41155 RefSeq (mRNA) NM_009588 NM_002341 NM_008518 RefSeq (protein) NP_002332 NP_033666 NP_032544 Location (UCSC) Chr 6: 31.58 – 31.58 Mb Chr 17: 35.41 – 35.42 Mb PubMed search [3] [4]
Wikidata
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Structure

Lymphotoxin-beta (LTB) is a type II membrane protein belonging to the TNF family. It forms heterotrimers with lymphotoxin-alpha, anchoring it to the cell surface. The predominant complex found on the surface of lymphocytes is the lymphotoxin-alpha 1/beta 2 complex (i.e., one molecule of alpha and two molecules of beta), which serves as the primary ligand for the lymphotoxin-beta receptor. A less common form is the lymphotoxin-alpha 2/beta 1 complex. Additionally, alternative splicing of the LTB gene results in multiple transcript variants encoding different isoforms. Notably, the lymphotoxin-beta isoform b cannot form a complex with lymphotoxin-alpha, indicating it may have functions independent of lymphotoxin-alpha.^[7]

Function

LTB plays a critical role in immune system regulation. It is an inducer of the inflammatory response and is essential for the normal development of lymphoid tissues. The membrane-bound lymphotoxin complexes mediate signaling through the lymphotoxin-beta receptor, influencing immune cell differentiation and tissue organization.^[7]

Clinical significance

The membrane-bound form of lymphotoxin has been implicated in tumorigenesis. Mice engineered to overexpress LTα or LTβ exhibit increased tumor growth and metastasis in several cancer models. However, earlier studies were limited by the use of mice lacking the entire LTα gene, making it difficult to distinguish the effects of soluble versus membrane-associated lymphotoxins.^[8]

Interactions

LTB has been shown to interact with Lymphotoxin alpha.^[9][10][11]