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Symbol SMG1 contributors: mct - updated : 11-09-2015
HGNC name SMG1 homolog, phosphatidylinositol 3-kinase-related kinase (C. elegans)
HGNC id 30045
Location 16p12.3      Physical location : 18.816.175 - 18.937.726
Synonym name
  • lambda-iota protein kinase C-interacting protein
  • phosphatidylinositol 3-kinase-related protein kinase
  • PI-3-kinase-related kinase SMG-1
  • suppressor of morphogenesis in genitalia-1
  • lambda-interacting protein
  • serine/threonine-protein kinase SMG1
  • Synonym symbol(s) KIAA0421, ATX, LIP, LIPKC, 61E3.4, SMG-1
    TYPE functioning gene
    STRUCTURE 121.55 kb     63 Exon(s)
    10 Kb 5' upstream gene genomic sequence study
    MAPPING cloned Y linked N status confirmed
    TRANSCRIPTS type messenger
    identificationnb exonstypebpproduct
    ProteinkDaAAspecific expressionYearPubmed
    63 splicing 16065 410.4 3661 - 2008 18326048
    - splicing 11036 340.7 3031 . widely . highly in heart, skeletal muscle, kidney and liver 2008 18326048
    a conserved ATP-binding site, a DXXXXN and a DXX motif within the catalytic domain and a short FATC C-terminal region common in PIK-related kinases
    Type ubiquitous
       expressed in (based on citations)
    SystemOrgan level 1Organ level 2Organ level 3Organ level 4LevelPubmedSpeciesStageRna symbol
    Endocrineadrenal gland   highly
     neuroendocrinepituitary  predominantly
     parathyroid   highly
    Nervousnervecranial nerve  moderately
    Reproductivefemale systembreastmammary gland highly
    Respiratoryrespiratory tractlarynx  highly
    SystemTissueTissue level 1Tissue level 2LevelPubmedSpeciesStageRna symbol
    cell lineage
    cell lines
    fluid/secretion highly in blood
    at STAGE
  • a FAT domain
  • a HEAT repeat
  • a PI3K/PI4K domain
  • a FATC domain
  • PI3K-related kinase (PIKK) family
  • phosphoinositide kinase-like kinase family
  • CATEGORY enzyme
    SUBCELLULAR LOCALIZATION     intracellular
    basic FUNCTION
  • involved in nonsense-mediated decay (NMD) of mRNAs containing premature stop codons by phosphorylating UPF1/RENT1
  • acting as a serine/threonine protein kinase involved in both mRNA surveillance and genotoxic stress response pathways
  • functioning in NMD by phosphorylating the regulator of nonsense transcripts 1 protein
  • may activate PRKCI
  • may function in telomere maintenance, responses to hypoxia, and TNFA–induced apoptosis
  • can phosphorylate TP53/p53 and is required for optimal TP53/p53 activation after cellular exposure to genotoxic stress
  • has a critical role in the degradation of premature termination codon (PTC)–containing transcripts mediated by the nonsense-mediated mRNA decay (NMD) pathway
  • recognizing the substrate consensus sequence [ST]-Q
  • playing an important role in cell survival during TNFalpha-induced stress
  • plays dual roles in mRNA surveillance and genotoxic stress response pathways in cells
  • proximal regulator of DNA damage signaling and the G(1) checkpoint is tightly regulated during prolonged oxidative stress by both phosphatidylinositol 3-kinase-like kinases-dependent synthesis and proteolysis of CDKN1A
  • activates the essential nonsense-mediated mRNA decay (NMD) factor UPF1
  • is a large kinase essential to nonsense-mediated mRNA decay (NMD) that phosphorylates UPF1, which seems to be the definitive signal triggering mRNA decay
  • SMG1 and MAP3K14 function as critical repressors of Smac mimetic compounds-mediated apoptosis by potentially converging on the regulation of CFLAR metabolism
  • activates TPp53 in response to DNA double-strand breaks independent of the RNA surveillance proteins UPF1 or UPF2
  • plays a central role in the process of stress granule formation
  • role in nonsense-mediated decay as well as suggested roles in the DNA damage response, resistance to oxidative stress, regulation of hypoxic responses, and apoptosis
  • participates likely in the regulation of inflammation and cancer development, and is a cancer susceptibility gene that may play a role in the pathogenesis of both lung and hematopoietic cancers
  • CELLULAR PROCESS cell life, antiapoptosis
    nucleotide, repair
    metabolism other
    mRNA catabolic process
    a component
  • component of a post-splicing multiprotein NMD complex with UPF1, UPF2/RENT2, EST1A (SMG5/7a), EST1B/SMG5 and UPF3 (UPF3A or UPF3B)
    small molecule metal binding,
  • Mn2+
  • Mg2+
  • protein
  • binding to lambda-iota protein kinase C
  • interacting with PRKCI
  • associated with TELO2 that is a highly conserved regulator of PIKK stability
  • SMG8 binding to the SMG1:SMG9 complex specifically down-regulates the kinase activity of SMG1 on UPF1 without contacting the catalytic domain
  • MARVELD1 promotes the dissociation of SMG1 from UPF1, resulting in the repression of serine phosphorylation of UPF1
  • SMG8 is involved in the recruitment of inactive SMG1 to the SURF complex
  • SMG1C (a complex containing SMG1, SMG8, and SMG9) contributes to regulate NMD by recruiting UPF1 and UPF2 to distinct sites in the vicinity of the kinase domain
  • UPF1 is recruited to the SMG1 kinase domain and C-terminal insertion domain, inducing an opening of the head domain that provides access to the active site
  • SMG8 and SMG9 act, in addition to serving as a scaffold for the interaction between SMG1 and UPF1, to negatively regulate SMG1 kinase activity and maintain UPF1 in the unphosphorylated (inactive) form within the SURF complex
  • cell & other
    inhibited by caffeine, LY294002 and wortmannin
    corresponding disease(s)
    Variant & Polymorphism
    Candidate gene
    Therapy target
  • essential for mouse embryogenesis such that Smg1 loss is lethal at embryonic day 8.5