FLT3LG
Available structures PDB Ortholog search: PDBe RCSB List of PDB id codes 1ETE, 3QS7, 3QS9
Identifiers
Aliases	FLT3LG, FL, FLT3L, fms related tyrosine kinase 3 ligand, FLG3L, fms related receptor tyrosine kinase 3 ligand
External IDs	OMIM: 600007 MGI: 95560 HomoloGene: 48021 GeneCards: FLT3LG
Gene location (Human) Chr. Chromosome 19 (human)[1] Band 19q13.33 Start 49,474,207 bp[1] End 49,486,231 bp[1]
Gene location (Mouse) Chr. Chromosome 7 (mouse)[2] Band 7 B3|7 29.14 cM Start 45,129,788 bp[2] End 45,136,432 bp[2]
RNA expression pattern Bgee Human Mouse (ortholog) Top expressed in blood lymph node canal of the cervix appendix gastric mucosa vagina subcutaneous adipose tissue spleen right coronary artery tibial nerve Top expressed in bone marrow spleen islet of Langerhans thymus urinary bladder lip esophagus jejunum duodenum colon More reference expression data BioGPS More reference expression data
Gene ontology Molecular function cytokine activity protein homodimerization activity receptor tyrosine kinase binding signaling receptor binding 1-phosphatidylinositol-3-kinase activity Cellular component integral component of membrane membrane intrinsic component of external side of plasma membrane plasma membrane cell surface extracellular region extracellular space intracellular anatomical structure Biological process positive regulation of protein phosphorylation positive regulation of natural killer cell differentiation lymphocyte differentiation positive regulation of cell proliferation in bone marrow negative regulation of apoptotic process in bone marrow cell positive regulation of myoblast fusion positive regulation of cell cycle positive regulation of myoblast differentiation positive regulation of cell population proliferation embryonic hemopoiesis homeostasis of number of cells within a tissue regulation of myeloid dendritic cell activation signal transduction positive regulation of transcription by RNA polymerase II positive regulation of osteoclast proliferation regulation of signaling receptor activity cytokine-mediated signaling pathway positive regulation of natural killer cell proliferation MAPK cascade phosphatidylinositol-3-phosphate biosynthetic process Sources:Amigo / QuickGO
Orthologs Species Human Mouse Entrez 2323 14256 Ensembl ENSG00000090554 ENSMUSG00000110206 UniProt P49771 P49772 RefSeq (mRNA) NM_001204502 NM_001204503 NM_001278637 NM_001278638 NM_001459 NM_013520 RefSeq (protein) NP_001191431 NP_001191432 NP_001265566 NP_001265567 NP_001450 NP_001191431.1 NP_038548 NP_001389760 NP_001389761 NP_001389762 NP_001389763 NP_001389764 NP_001389765 NP_001389766 Location (UCSC) Chr 19: 49.47 – 49.49 Mb Chr 7: 45.13 – 45.14 Mb PubMed search [3] [4]
Wikidata
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Fms-related tyrosine kinase 3 ligand (FLT3LG) is a protein which in humans is encoded by the FLT3LG gene.^[5][6][7]

Flt3 ligand (FL) is a hematopoietic four helical bundle cytokine. It is structurally homologous to stem cell factor (SCF) and colony stimulating factor 1 (CSF-1). In synergy with other growth factors, Flt3 ligand stimulates the proliferation and differentiation of various blood cell progenitors. For example, it is a major growth factor stimulating the growth of dendritic cells.^[8]

FLT3L functions as a cytokine and growth factor that increases the number of immune cells (lymphocytes (B cells and T cells)) by activating the hematopoietic progenitors. It acts by binding to and activating FLT3 (CD135) which is found on what (in mice) are called multipotent progenitor (MPP) and common lymphoid progenitor (CLP) cells. It also induces the mobilization of the hematopoietic progenitors and stem cells in vivo which may help the system to kill cancer cells.^[9]

FLT3L is crucial for steady-state plasmacytoid dendritic cell (pDC) and classical dendritic cell (cDC) development.^[9][10] A lack of FLT3L results in low levels of dendritic cells.

In parasite clearance

FLT3L and its receptor are involved in the mammalian immune response to malaria. In strains of plasmodium, FLT3L was shown to be released from mast cells and cause the expansion of dendritic cells, leading to the activation of CD8+ T cells. The same paper suggested that FLT3L release was caused by stimulation of mast cells with uric acid, produced from a precursor secreted by the plasmodium parasite. .^[11]

In immunotherapy

In situ vaccine (ISV), combining Flt3L, local radiotherapy, and a TLR3 agonist (poly-ICLC), could recruit, antigen-load and activate intratumoral cross-presenting dendritic cells (DCs) in indolent non-Hodgkin’s lymphomas (iNHLs) treatment (clinical trial: NCT01976585).^[12] In this study, intratumoral Flt3L was able to (1) induce the accumulation of large numbers of TLR3+ DCs in the tumor and (2) mediate , together with local irradiation, cross-presentation of TAA by DCs in vitro and in vivo.