STARD4

STARD4
Identifiers
Aliases	STARD4, StAR related lipid transfer domain containing 4
External IDs	OMIM: 607049; MGI: 2156764; GeneCards: STARD4
Gene location (Human) Chr. Chromosome 5 (human)[1] Band 5q22.1 Start 111,496,033 bp[1] End 111,512,590 bp[1]
Gene location (Mouse) Chr. Chromosome 18 (mouse)[2] Band 18 B1|18 18.18 cM Start 33,332,408 bp[2] End 33,346,915 bp[2]
RNA expression pattern Bgee Human Mouse (ortholog) Top expressed in mucosa of ileum jejunal mucosa duodenum right hemisphere of cerebellum rectum right lung appendix islet of Langerhans upper lobe of left lung pancreatic ductal cell Top expressed in crypt of lieberkuhn of small intestine epithelium of small intestine left colon ileum intestinal villus jejunum migratory enteric neural crest cell left lung lobe pineal gland left lobe of liver More reference expression data BioGPS n/a
Gene ontology Molecular function lipid binding cholesterol binding cholesterol transfer activity Cellular component mitochondrion cytoplasmic vesicle Biological process lipid transport positive regulation of cholesterol esterification cholesterol import positive regulation of bile acid biosynthetic process cholesterol transport involved in cholesterol storage intracellular cholesterol transport Sources:Amigo / QuickGO
Orthologs Databases NCBI: entry; OMA: entry Species Human Mouse Entrez 134429 170459 Ensembl ENSG00000164211 ENSMUSG00000024378 UniProt Q96DR4 Q99JV5 RefSeq (mRNA) NM_001308056 NM_001308057 NM_001308058 NM_001308059 NM_001308060 NM_001308061 NM_139164 NM_133774 NM_001347624 NM_180986 RefSeq (protein) NP_001294985 NP_001294986 NP_001294987 NP_001294988 NP_001294989 NP_001294990 NP_631903 NP_001334553 NP_598535 Location (UCSC) Chr 5: 111.5 – 111.51 Mb Chr 18: 33.33 – 33.35 Mb PubMed search [3] [4]
Wikidata
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StAR-related lipid transfer protein 4 (STARD4) is a soluble protein involved in cholesterol transport. It can transfer up to 7 sterol molecules per minute between artificial membranes.^[5]

STARD4 may regulate cholesterol levels in many cells, including in the liver. STARD4 has specifically been linked to the movement of cholesterol to the endoplasmic reticulum. The protein is associated with the endoplasmic reticulum and lipid droplets.^[6] Increases in the protein levels are assoaciated with cell stress.^[7]

High levels of STARD4 increases the synthesis of bile acids and cholesterol esters in liver hepatocytes.^[8] Reductions in cholesterol synthesis by cells increase STARD4 levels while StarD4 declines in mice fed a high cholesterol diet.^[9][10]

Increases in levels of either master gene regulator SREBP-1a or SREBP2, which both promote the production of proteins involved in cholesterol synthesis, increase StarD4 levels in mouse liver.^[11] Conversely, increased STARD4 increases active SREBP2 levels.

Loss of the protein in mice has little effect.^[12] Mice without functional STARD4 weigh less and females tend to have lower cholesterol profiles. The most dramatic change observed to date is a reduction in NPC-1, a protein involved in bringing cholesterol into cells.

The protein is 205 amino acids long in the human (224 in the mouse) and almost entirely consists of a StAR-related transfer (START) domain. It also lends its name to the subgroup of START domain proteins it is part of, StarD4. This subfamily includes STARD5 and STARD6 and is closely related to the StarD1/D3 group.