STARD3
Available structures
PDBOrtholog search: PDBe RCSB
Identifiers
AliasesSTARD3, CAB1, MLN64, es64, StAR related lipid transfer domain containing 3
External IDsOMIM: 607048 MGI: 1929618 HomoloGene: 38227 GeneCards: STARD3
Orthologs
SpeciesHumanMouse
Entrez

10948

59045

Ensembl

ENSG00000131748

ENSMUSG00000018167

UniProt

Q14849

Q61542

RefSeq (mRNA)

NM_001165937
NM_001165938
NM_006804

NM_021547

RefSeq (protein)

NP_001159409
NP_001159410
NP_006795

NP_067522

Location (UCSC)Chr 17: 39.64 – 39.66 MbChr 11: 98.25 – 98.27 Mb
PubMed search[3][4]
Wikidata
View/Edit HumanView/Edit Mouse

StAR related lipid transfer domain containing 3 (STARD3) is a protein that in humans is encoded by the STARD3 gene.[5] STARD3 also known as metastatic lymph node 64 protein (MLN64) is a late endosomal integral membrane protein involved in cholesterol transport.[6] STARD3 creates membrane contact sites between the endoplasmic reticulum (ER) and late endosomes where it moves cholesterol.[7][8]

Function

This gene encodes a member of a subfamily of lipid trafficking proteins that are characterized by a C-terminal steroidogenic acute regulatory domain and an N-terminal metastatic lymph node 64 domain. The encoded protein localizes to the membranes of late endosomes and may be involved in exporting cholesterol. Alternative splicing results in multiple transcript variants.[provided by RefSeq, Oct 2009].

STARD3 is involved in cholesterol transport from the ER to late endosomes where the protein is anchored.[9][10] It forms a complex with fellow late endosomal protein STARD3 N-terminal-like protein (STARD3NL) also known as MLN64 N-terminal homologue (MENTHO) and ER VAMP-associated proteins (VAP proteins) A and B (VAP-A, VAP-B) to tether the two organelles together.[11] For STARD3, this interaction is regulated by phosphorylation of a serine in its FFAT motif.[12]

The closest homolog to STARD3 is the steroidogenic acute regulatory protein (StAR/StarD1), which initiates the production of steroids by moving cholesterol inside the mitochondrion. Thus, MLN64 is also proposed to move cholesterol inside the mitochondria under certain conditions to initiate StAR-independent steroidogenesis, such as in the human placenta which lacks StAR yet produces steroids.[13] This functional role is supported by evidence that MLN64 expression can stimulate steroid production in a model cell system.[13]

One study indicates that this protein also specifically binds lutein in the retina.[14]

Structure

STARD3 is a multi-domain protein composed of a N-terminal MENTAL (MLN64 N-terminal) domain, a central phospho-FFAT motif (two phenylalanines in an acidic tract), and a C-terminal StAR-related transfer domain (START) lipid transport domain.

The MENTAL domain of STARD3 is similar to the protein STARD3 N-terminal like protein (STARD3NL) also known as MLN64 N-terminal homologue (MENTHO).[15] This domain is composed of 4 transmembrane helices which anchor the protein in the limiting membrane of late endosomes. This domain binds cholesterol and associates with the same domain in STARD3NL.[16]

The phospho-FFAT motif is a short protein sequence motif which binds to the ER proteins VAP-A, VAP-B and MOSPD2 proteins after phosphorylation.[12]

The START domain of STARD3 is homologous to the StAR protein. X-ray crystallography of the C-terminus indicates that this domain forms a pocket that can bind cholesterol.[17] This places STARD3 within the StarD1/D3 subfamily of START domain-containing proteins.

Tissue distribution

STARD3 is expressed in all tissues in the body at various levels. In the brain, MLN64 is detectable in many but not all cells.[18] Many malignant tumors highly express STARD3 as a result of its gene being part of a Her2/erbB2-containing gene locus that is amplified.

Pathology

Loss of STARD3 has little effect in mice.[19] At the cellular level, changes in STARD3 can disrupt trafficking of endosomes and cause accumulation of cholesterol in late endosomes.[20]

References

  1. 1 2 3 GRCh38: Ensembl release 89: ENSG00000131748 - Ensembl, May 2017
  2. 1 2 3 GRCm38: Ensembl release 89: ENSMUSG00000018167 - Ensembl, May 2017
  3. "Human PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
  4. "Mouse PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
  5. "Entrez Gene: StAR related lipid transfer domain containing 3". Retrieved 2018-08-07.
  6. Alpy F, Tomasetto C (June 2006). "MLN64 and MENTHO, two mediators of endosomal cholesterol transport". Biochemical Society Transactions. 34 (Pt 3): 343–5. doi:10.1042/BST0340343. PMID 16709157.
  7. Wilhelm LP, Wendling C, Védie B, Kobayashi T, Chenard MP, Tomasetto C, Drin G, Alpy F (May 2017). "STARD3 mediates endoplasmic reticulum-to-endosome cholesterol transport at membrane contact sites". The EMBO Journal. 36 (10): 1412–1433. doi:10.15252/embj.201695917. PMC 5430228. PMID 28377464.
  8. Alpy F, Rousseau A, Schwab Y, Legueux F, Stoll I, Wendling C, Spiegelhalter C, Kessler P, Mathelin C, Rio MC, Levine TP, Tomasetto C (December 2013). "STARD3 or STARD3NL and VAP form a novel molecular tether between late endosomes and the ER". Journal of Cell Science. 126 (Pt 23): 5500–12. doi:10.1242/jcs.139295. PMID 24105263.
  9. Wilhelm LP, Wendling C, Védie B, Kobayashi T, Chenard MP, Tomasetto C, Drin G, Alpy F (May 2017). "STARD3 mediates endoplasmic reticulum-to-endosome cholesterol transport at membrane contact sites". The EMBO Journal. 36 (10): 1412–1433. doi:10.15252/embj.201695917. PMC 5430228. PMID 28377464.
  10. Alpy F, Stoeckel ME, Dierich A, Escola JM, Wendling C, Chenard MP, Vanier MT, Gruenberg J, Tomasetto C, Rio MC (February 2001). "The steroidogenic acute regulatory protein homolog MLN64, a late endosomal cholesterol-binding protein". The Journal of Biological Chemistry. 276 (6): 4261–9. doi:10.1074/jbc.M006279200. PMID 11053434.
  11. Alpy F, Rousseau A, Schwab Y, Legueux F, Stoll I, Wendling C, Spiegelhalter C, Kessler P, Mathelin C, Rio MC, Levine TP, Tomasetto C (December 1, 2013). "STARD3 or STARD3NL and VAP form a novel molecular tether between late endosomes and the ER" (PDF). J Cell Sci. 126 (23): 5500–5512. doi:10.1242/jcs.139295. PMID 24105263. S2CID 7245863.
  12. 1 2 Di Mattia, Thomas; Martinet, Arthur; Ikhlef, Souade; McEwen, Alastair G; Nominé, Yves; Wendling, Corinne; Poussin-Courmontagne, Pierre; Voilquin, Laetitia; Eberling, Pascal; Ruffenach, Frank; Cavarelli, Jean; Slee, John; Levine, Timothy P; Drin, Guillaume; Tomasetto, Catherine; Alpy, Fabien (December 1, 2020). "FFAT motif phosphorylation controls formation and lipid transfer function of inter-organelle contacts". The EMBO Journal. 39 (23): e104369. doi:10.15252/embj.2019104369. ISSN 0261-4189. PMC 7705450. PMID 33124732.
  13. 1 2 Watari H, Arakane F, Moog-Lutz C, Kallen CB, Tomasetto C, Gerton GL, Rio MC, Baker ME, Strauss JF (August 1997). "MLN64 contains a domain with homology to the steroidogenic acute regulatory protein (StAR) that stimulates steroidogenesis". Proceedings of the National Academy of Sciences of the United States of America. 94 (16): 8462–7. Bibcode:1997PNAS...94.8462W. doi:10.1073/pnas.94.16.8462. PMC 22957. PMID 9237999.
  14. Li B, Vachali P, Frederick JM, Bernstein PS (April 2011). "Identification of StARD3 as a lutein-binding protein in the macula of the primate retina". Biochemistry. 50 (13): 2541–9. doi:10.1021/bi101906y. PMC 3070171. PMID 21322544.
  15. Alpy F, Wendling C, Rio MC, Tomasetto C (December 2002). "MENTHO, a MLN64 homologue devoid of the START domain". The Journal of Biological Chemistry. 277 (52): 50780–7. doi:10.1074/jbc.M208290200. PMID 12393907.
  16. Alpy F, Latchumanan VK, Kedinger V, Janoshazi A, Thiele C, Wendling C, Rio MC, Tomasetto C (May 2005). "Functional characterization of the MENTAL domain". The Journal of Biological Chemistry. 280 (18): 17945–52. doi:10.1074/jbc.M500723200. PMID 15718238.
  17. Tsujishita Y, Hurley JH (May 2000). "Structure and lipid transport mechanism of a StAR-related domain". Nature Structural Biology. 7 (5): 408–14. doi:10.1038/75192. PMID 10802740. S2CID 10806665.
  18. King SR, Smith AG, Alpy F, Tomasetto C, Ginsberg SD, Lamb DJ (2006). "Characterization of the putative cholesterol transport protein metastatic lymph node 64 in the brain". Neuroscience. 139 (3): 1031–8. doi:10.1016/j.neuroscience.2006.01.063. PMID 16549269. S2CID 33113555.
  19. Kishida T, Kostetskii I, Zhang Z, Martinez F, Liu P, Walkley SU, Dwyer NK, Blanchette-Mackie EJ, Radice GL, Strauss JF (April 2004). "Targeted mutation of the MLN64 START domain causes only modest alterations in cellular sterol metabolism". The Journal of Biological Chemistry. 279 (18): 19276–85. doi:10.1074/jbc.M400717200. PMID 14963026.
  20. Zhang M, Liu P, Dwyer NK, Christenson LK, Fujimoto T, Martinez F, Comly M, Hanover JA, Blanchette‐Mackie EJ, Strauss JF (2002) MLN64 mediates mobilization of lysosomal cholesterol to steroidogenic mitochondria. J Biol Chem 277: 33300–33310 [PubMed] doi: 10.1074/jbc.M200003200

Further reading

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