From Wikipedia, the free encyclopedia
Jump to: navigation, search
Protein FIS1 PDB 1iyg.png
Available structures
PDB Ortholog search: PDBe RCSB
Aliases FIS1, TTC11, CGI-135, fission, mitochondrial 1
External IDs MGI: 1913687 HomoloGene: 41099 GeneCards: FIS1
Species Human Mouse
RefSeq (mRNA)



RefSeq (protein)



Location (UCSC) Chr 7: 101.24 – 101.25 Mb Chr 5: 136.95 – 136.97 Mb
PubMed search [1] [2]
View/Edit Human View/Edit Mouse

Mitochondrial fission 1 protein (FIS1) is a protein that in humans is encoded by the FIS1 gene on chromosome 7.[3][4][5] This protein is a component of a mitochondrial complex, the ARCosome, that promotes mitochondrial fission.[5][6] Its role in mitochondrial fission thus implicates it in the regulation of mitochondrial morphology, the cell cycle, and apoptosis.[5][6][7][7][8] By extension, the protein is involved in associated diseases, including neurodegenerative diseases and cancers.[9][10]


The protein encoded by this gene is a 16 kDa integral protein situated in the outer mitochondrial membrane (OMM).[7] It is composed of a transmembrane domain at the C-terminal and a cytosolic domain at the N-terminal.[7][11][12] The transmembrane domain anchors FIS1 in the OMM, though it has been observed to target different cellular compartments, such as the peroxisome, depending on its hydrophobicity, charge, and length.[12][13] Meanwhile, the cytosolic domain contains a bundle of six helices, four of which contain two tandem tetratricopeptide repeat (TPR)-like motifs. These motifs form a concave surface by their combined superhelical structure and potentially bind another FIS1 protein to form a dimer, or other proteins.[7][11] Moreover, the N-terminal arm can dock at, and thus obstruct, the TPR motifs, allowing the protein to exist in a dynamic equilibrium between “open” and “closed” states.[11]


FIS1 is indirectly involved in mitochondrial fission via binding dynamin-related protein 1 (DRP1).[10][13] By extension, FIS1 helps regulate the size and distribution of mitochondria in response to local demand for ATP or calcium ions.[11] In addition, mitochondrial fission may lead to release of cytochrome C, which eventually leads to cell death.[7] In a separate apoptotic signalling pathway, FIS1 interacts with BCAP31 to form a complex, the ARCosome. The ARCosome promotes cell death by bridging the mitochondria and the endoplasmic reticulum (ER), allowing FIS1 to transmit a proapoptotic signal from the mitochondria to the ER and activate procaspase-8. The ARCosome then forms a platform with procaspase-8 to increase calcium load in the mitochondria, resulting in apoptosis.[6][10] Additionally, FIS1 is involved in other modes of shaping mitochondrial morphology. For example, it interacts with TBC1D15 to regulate mitochondrial morphology, particularly with regard to lysosome and endosome fusion.[12] FIS1 also prevents mitochondria elongation, which would otherwise lead to cell cycle delay or arrest, and ultimately, senescence. Moreover, mitochondrial dysfunction results in elevated reactive oxygen species (ROS) levels, which cause DNA damage and induce transcriptional repression, as well as induce mitophagy.[7][8]

Clinical Significance[edit]

As a fission factor, FIS1 is associated with neurodegenerative diseases.[9][10] Stress, such as NO, can trigger aberrant mitochondrial fission and fusion, resulting in mitophagy.[7][9] For example, increased mitochondrial fragmentation and FIS1 levels were observed in Alzheimer’s disease (AD) patients. Thus, FIS1 could serve as a biomarker for early detection of AD.[9] FIS1 is also implicated in a variety of cancers, including acute myeloid leukemia, breast cancer, and prostate cancer.[10]


FIS1 has been shown to interact with:


  1. ^ "Human PubMed Reference:". 
  2. ^ "Mouse PubMed Reference:". 
  3. ^ Stojanovski D, Koutsopoulos OS, Okamoto K, Ryan MT (Mar 2004). "Levels of human Fis1 at the mitochondrial outer membrane regulate mitochondrial morphology". Journal of Cell Science. 117 (Pt 7): 1201–10. doi:10.1242/jcs.01058. PMID 14996942. 
  4. ^ Kong D, Xu L, Yu Y, Zhu W, Andrews DW, Yoon Y, Kuo TH (Apr 2005). "Regulation of Ca2+-induced permeability transition by Bcl-2 is antagonized by Drpl and hFis1". Molecular and Cellular Biochemistry. 272 (1-2): 187–99. doi:10.1007/s11010-005-7323-3. PMID 16010987. 
  5. ^ a b c "Entrez Gene: FIS1 fission 1 (mitochondrial outer membrane) homolog (S. cerevisiae)". 
  6. ^ a b c d e Iwasawa R, Mahul-Mellier AL, Datler C, Pazarentzos E, Grimm S (Feb 2011). "Fis1 and Bap31 bridge the mitochondria-ER interface to establish a platform for apoptosis induction". The EMBO Journal. 30 (3): 556–68. doi:10.1038/emboj.2010.346. PMID 21183955. 
  7. ^ a b c d e f g h Gomes LC, Scorrano L (2008). "High levels of Fis1, a pro-fission mitochondrial protein, trigger autophagy". Biochimica et Biophysica Acta. 1777 (7-8): 860–6. doi:10.1016/j.bbabio.2008.05.442. PMID 18515060. 
  8. ^ a b Lee S, Park YY, Kim SH, Nguyen OT, Yoo YS, Chan GK, Sun X, Cho H (Feb 2014). "Human mitochondrial Fis1 links to cell cycle regulators at G2/M transition". Cellular and Molecular Life Sciences. 71 (4): 711–25. doi:10.1007/s00018-013-1428-8. PMID 23907611. 
  9. ^ a b c d Wang S, Song J, Tan M, Albers KM, Jia J (Jul 2012). "Mitochondrial fission proteins in peripheral blood lymphocytes are potential biomarkers for Alzheimer's disease". European Journal of Neurology. 19 (7): 1015–22. doi:10.1111/j.1468-1331.2012.03670.x. PMID 22340708. 
  10. ^ a b c d e Tian Y, Huang Z, Wang Z, Yin C, Zhou L, Zhang L, Huang K, Zhou H, Jiang X, Li J, Liao L, Yang M, Meng F (2014). "Identification of novel molecular markers for prognosis estimation of acute myeloid leukemia: over-expression of PDCD7, FIS1 and Ang2 may indicate poor prognosis in pretreatment patients with acute myeloid leukemia". PLOS ONE. 9 (1): e84150. doi:10.1371/journal.pone.0084150. PMC 3885535Freely accessible. PMID 24416201. 
  11. ^ a b c d Lees JP, Manlandro CM, Picton LK, Tan AZ, Casares S, Flanagan JM, Fleming KG, Hill RB (Oct 2012). "A designed point mutant in Fis1 disrupts dimerization and mitochondrial fission". Journal of Molecular Biology. 423 (2): 143–58. doi:10.1016/j.jmb.2012.06.042. PMID 22789569. 
  12. ^ a b c d Onoue K, Jofuku A, Ban-Ishihara R, Ishihara T, Maeda M, Koshiba T, Itoh T, Fukuda M, Otera H, Oka T, Takano H, Mizushima N, Mihara K, Ishihara N (Jan 2013). "Fis1 acts as a mitochondrial recruitment factor for TBC1D15 that is involved in regulation of mitochondrial morphology". Journal of Cell Science. 126 (Pt 1): 176–85. doi:10.1242/jcs.111211. PMID 23077178. 
  13. ^ a b c Palmer CS, Elgass KD, Parton RG, Osellame LD, Stojanovski D, Ryan MT (Sep 2013). "Adaptor proteins MiD49 and MiD51 can act independently of Mff and Fis1 in Drp1 recruitment and are specific for mitochondrial fission". The Journal of Biological Chemistry. 288 (38): 27584–93. doi:10.1074/jbc.M113.479873. PMID 23921378. 
  14. ^ Yoon Y, Krueger EW, Oswald BJ, McNiven MA (Aug 2003). "The mitochondrial protein hFis1 regulates mitochondrial fission in mammalian cells through an interaction with the dynamin-like protein DLP1". Molecular and Cellular Biology. 23 (15): 5409–20. doi:10.1128/MCB.23.15.5409-5420.2003. PMC 165727Freely accessible. PMID 12861026. 

Further reading[edit]