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Symbol SPART contributors: mct/shn - updated : 22-01-2020
HGNC name spastic paraplegia 20 (Troyer syndrome)
HGNC id 18514
Corresponding disease
SPG20 spastic paraplegia 20
Location 13q13.3      Physical location : -
Synonym name
  • spartin
  • trans-activated by hepatitis C virus core protein 1
  • Synonym symbol(s) TAHCCP1, SPARTIN, KIAA0610, SPG20
    TYPE functioning gene
    STRUCTURE 68.54 kb     10 Exon(s)
    MAPPING cloned Y linked N status provisional
    Map cen - D13S1293 - D13S894 - SPG20 - D13S219 - D13S894 - qter
    TRANSCRIPTS type messenger
    text all transcripts encode the same protein
    identificationnb exonstypebpproduct
    ProteinkDaAAspecific expressionYearPubmed
    9 splicing 4838 - 666 - 2009 19765186
    9 splicing 4962 - 666 - 2009 19765186
    10 splicing 5014 - 666 - 2009 19765186
    9 splicing 5031 - 666 - 2009 19765186
    Type widely
       expressed in (based on citations)
    SystemOrgan level 1Organ level 2Organ level 3Organ level 4LevelPubmedSpeciesStageRna symbol
    Cardiovascularheartatrium  moderately Homo sapiensAdult
    Digestiveintestinelarge intestinerectum highly Homo sapiensAdult
     intestinelarge intestinecolon lowly Homo sapiensAdult
     intestinesmall intestine  moderately Homo sapiensAdult
     liver   highly Homo sapiensAdult
     stomach   highly Homo sapiensAdult
    Endocrineadrenal gland   highly Homo sapiensAdult
     pancreas   moderately Homo sapiensAdult
     thyroid   lowly Homo sapiensAdult
    Lymphoid/Immunelymph node   lowly Homo sapiensAdult
     spleen   moderately Homo sapiensAdult
     thymus   highly Homo sapiensAdult
    Nervousbrainforebraincerebral lobefrontal lobemoderately Homo sapiensAdult
     brainhindbrainpons moderately Homo sapiensAdult
     brainforebraincerebral lobetemporal lobehighly Homo sapiensAdult
     braindiencephalonthalamus moderately Homo sapiensAdult
     brainforebraincerebral lobeparietal lobemoderately Homo sapiensAdult
     brainforebraincerebral lobeoccipital lobemoderately Homo sapiensAdult
     brainhindbraincerebellum highly Homo sapiensAdult
     spinal cord   lowly Homo sapiensAdult
    Reproductivefemale systemovary  lowly Homo sapiensAdult
     female systembreast  moderately Homo sapiensAdult
     female systemuterus  moderately Homo sapiensAdult
     female systemplacenta  highly Homo sapiensAdult
     male systemtestis  moderately Homo sapiensAdult
    Respiratorylung   moderately Homo sapiensAdult
     respiratory tracttrachea  moderately Homo sapiensAdult
    Urinarybladder   moderately Homo sapiensAdult
     kidney   lowly Homo sapiensAdult
    SystemTissueTissue level 1Tissue level 2LevelPubmedSpeciesStageRna symbol
    Muscularstriatumskeletal moderately Homo sapiensAdult
    cell lineage
    cell lines
    at STAGE
  • a MIT domain (contained within microtubule-intreacting and trafficking molecules)
  • an ESP domain
  • mono polymer aggregate
    interspecies homolog to spastic paraplegia 20, spartin (Troyer syndrome) homolog (human) , Mus musculus
    ortholog to spastic paraplegia 20 (Troyer syndrome), Pan troglodytes
    homolog to spastic paraplegia 20, spartin (Troyer syndrome) homolog (human) , Rattus norvegicus
    CATEGORY regulatory
    SUBCELLULAR LOCALIZATION     plasma membrane
  • co-localization with microtubules
  • localizes to mitochondria dependending on sequences in the C-terminal region
  • upon EGF stimulation, spartin translocates from the cytoplasm to the plasma membrane and colocalizes with internalized EGF-Alexa
  • exists in a cytosolic pool that can be recruited to endosomes and to lipid droplets
  • localize to the endosomal membrane traffic compartment, suggesting that the long axons of the corticospinal tract may be especially vulnerable to endosomal dysfunction
  • localizes to mitochondria and this localization is dependent on sequences in the C-terminal region (mutant spartin containing the 1110delA mutation has lost mitochondrial localization)
  • colocalizes with IST1 at the midbody, and depletion of IST1 in cells by small interfering RNA significantly decreases the number of cells where spartin is present at midbodies
  • basic FUNCTION
  • involved in microtubule interaction
  • may be involved in endocytosis, vesicle trafficking, or mitogenic activity
  • mono-ubiquitinated and functioning in degradation of the epidermal growth factor receptor (EGFR) involved in the intracellular trafficking of EGFR (Bakowska 2007)
  • involved in the intracellular trafficking of EGFR (Bakowska 2007)
  • inhibitor of BMP signalling in neuronal and non-neuronal cells (Tsang 2009)
  • acts as an adaptor for WWP1 and ITCH (Edwards 2009)
  • involved in diverse cellular functions, which may be of relevance to the complex phenotype seen in Troyer syndrome (Edwards 2009)
  • multifunctional protein and that may have a role in protein folding and turnover both in mitochondria and endoplasmic reticulum (Milewska 2009)
  • a role in the regulation of lipid droplets turnover
  • SPART is involved in many cellular processes and associates with several intracellular organelles, including mitochondria.
  • inhibits bone morphogenetic protein signaling by promoting endocytic degradation of BMP receptor wishful thinking
  • regulates synaptic growth and function
  • regulates both synaptic development and neuronal survival by controlling microtubule stability via the BMP-dFMRP-Futsch pathway
  • there is a critical level of spartin expression which must be maintained for proper cellular functions
    a component
    small molecule other,
  • associates with the surface of lipid droplets (LDs) and can regulate their size and number (Eastman 2009)
  • protein
  • epidermal growth factor receptor pathway substrate 15, EPS15
  • ubiquitin and the E3 ubiquitin-protein ligases, ITCH and WWP1
  • binds to another lipid droplets (LD) protein, M6PRBP1, and both proteins compete with an additional LD protein, adipophilin/adipocyte differentiation-related protein, for occupancy of LDs (Eastman 2009)
  • PPXY motif with the ubiquitin E3 ligases atrophin-interacting protein 4, AIP4; itchy E3 ubiquitin protein ligase homologue, ITCH and WW domain containing E3 ubiquitin protein ligase 1, WWP1
  • IST1 interaction is important for SPART recruitment to the midbody , suggesting that SPART participates in cytokinesis
  • FK506
  • efficient abscission during cytokinesis requires proper function of the ESCRT-III protein IST1, which binds to the microtubule interacting and trafficking (MIT) domains of VPS4A, VTA1, and SPART via its C-terminal MIT-interacting motif (MIM)
  • cell & other
    corresponding disease(s) SPG20
    Other morbid association(s)
    TypeGene ModificationChromosome rearrangementProtein expressionProtein Function
    tumoral     --low  
    hypermethylated in 89p100 of colorectal carcinomas, 78p100 of adenomas and only 1p100 of normal mucosa samples
    tumoral     --low  
    in cancer cells resulted in cytokinesis arrest, which was reversed when SPG20 methylation was inhibited
    Variant & Polymorphism
    Candidate gene
    Therapy target
  • SPG20 promoter hypermethylation as a biomarker suitable for non-invasive detection of colorectal cancer, and a possible mechanism for cytokinesis arrest in colorectal tumorigenesis
  • Loss of Spartin in Drosophila induces age-dependent progressive defects resembling hereditary spastic paraplegias, including motor dysfunction and brain neurodegeneration