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FLASH GENE
Symbol LAPTM4B contributors: mct/pgu - updated : 27-08-2013
HGNC name lysosomal protein transmembrane 4 beta
HGNC id 13646
Location 8q22.1      Physical location : 98.787.808 - 98.864.829
Synonym name
  • lysosomal associated protein transmembrane 4 beta
  • putative integral membrane transporter
  • LAPTM4B protein
  • Synonym symbol(s) LC27, LAPTM4beta
    DNA
    TYPE functioning gene
    STRUCTURE 77.02 kb     7 Exon(s)
    10 Kb 5' upstream gene genomic sequence study
    MAPPING cloned Y linked N status provisional
    RNA
    TRANSCRIPTS type messenger
    identificationnb exonstypebpproduct
    ProteinkDaAAspecific expressionYearPubmed
    7 - 2242 35.1 317 - 2004 15162524
  • also called LAPTM4B-35
  • expression upregulated and associated with poor differentiation in human HCC tissue
  • LAPTM4B-35 level in cancer is evidenced to be an independent prognostic factor and its upregulation promotes cell proliferation, migration and invasion
  • new role of LAPTM4B-35 in promoting multidrug resistance of cancer cells
  • - - 2242 - - - 2004 15162524
    also called LAPTM4B-24
    EXPRESSION
    Type ubiquitous
       expressed in (based on citations)
    organ(s)
    SystemOrgan level 1Organ level 2Organ level 3Organ level 4LevelPubmedSpeciesStageRna symbol
    Cardiovascularheart   highly
    Digestiveintestinesmall intestine   
    Reproductivefemale systemovary  highly
     female systemuteruscervix  
     male systemtestis   
    Respiratoryrespiratory tractlarynx  highly
    Visualeye   highly
    tissue
    SystemTissueTissue level 1Tissue level 2LevelPubmedSpeciesStageRna symbol
    Connectivebone  highly
    Muscularstriatumskeletal  
    Nervousperipherous   
    cell lineage
    cell lines
    fluid/secretion
    at STAGE
    physiological period fetal
    Text liver, highly
    PROTEIN
    PHYSICAL PROPERTIES
    STRUCTURE
    motifs/domains
  • PPRP motif in the N-terminal region of LAPTM4B-35 plays a critical role in promoting proliferation, migration, and invasion
  • four putative transmembrane regions
  • both the N- and C-termini are proline-rich, and may serve as potential ligands for the SH3 domain
  • conjugated GlycoP , PhosphoP
    HOMOLOGY
    interspecies homolog to murine Laptm4b (92.5pc)
    homolog to rattus Laptm4b (93.4pc)
    homolog to zebrafish laptm4b
    Homologene
    FAMILY
  • LAPTM4/LAPTM5 transporter family
  • lysosome associated protein transmembrane (LAPTM) family
  • CATEGORY protooncogene , transport
    SUBCELLULAR LOCALIZATION     plasma membrane
        intracellular
    intracellular,cytoplasm,organelle,membrane
    intracellular,cytoplasm,organelle,endoplasmic reticulum
    intracellular,cytoplasm,organelle,Golgi
    intracellular,cytoplasm,organelle,endosome
    intracellular,cytoplasm,organelle,lysosome
    intracellular,nuclear envelope
    text
  • LAPTM4A and LAPTM4B are localized to the lysosome
  • a fraction of LAPTM4B is present at the plasma membrane
  • basic FUNCTION
  • a potential protooncogene activity, whose over-expression is involved in carcinogenesis and progression of hepatocellular carcinoma
  • may also play roles such as regulation of cell proliferation and survival in normal cells
  • may be playing a dual functional role during tumor progression
  • involved in chemoresistance to anthracyclines and metastatic receurrence in breast cancer, by sequestering anthracyclines and delayed entry into the nucleus
  • promoting cell proliferation and tumorigenesis through regulation of the cell ceycle and signaling pathways
  • acts on anthracycline trafficking by reducing drug entry into the nucleus and decreasing drug-induced DNA damage
  • required for lysosome homeostasis, acidification, and function, and renders tumor cells resistant to lysosome-mediated cell death triggered by environmental and genotoxic stresses
  • cancer-associated gene, playing an important role in lysosomal functions and is critical for autophagic maturation
  • CELLULAR PROCESS cell life, proliferation/growth
    PHYSIOLOGICAL PROCESS
    PATHWAY
    metabolism
    signaling
    a component
    INTERACTION
    DNA
    RNA
    small molecule
    protein
    cell & other
    REGULATION
    ASSOCIATED DISORDERS
    corresponding disease(s)
    Other morbid association(s)
    TypeGene ModificationChromosome rearrangementProtein expressionProtein Function
    tumoral     --over  
    in hepatocellular carcinoma (
    tumoral     --over  
    in breast, ovary, uterus, lung, colon carcinoma
    tumoral     --over  
    contribute to de novo chemoresistance to anthracyclines and are permissive for metastatic recurrence (
    tumoral     --over  
    may contribute to the tumor progression and poor prognosis of breast cancer
    Susceptibility
    Variant & Polymorphism SNP
  • allele *2 of LAPMT4B might be the risk factor of gastric cancer, which could be associated with genetic susceptibility of gastric cancer and also for lung cancer
  • polymorphism associated with increased risk of colon cancer
  • Candidate gene
    Marker
  • may be a clinically useful prognostic indicator for ovarian carcinoma )
  • may be a novel marker for the prediction of recurrence and metastasis potency of hepatocellular carcinoma
  • testing the expression of LAPTM4B will be helpful for predicting prognosis in breast cancer
  • Therapy target
  • target suitable for development of novel therapeutic agents
  • SystemTypeDisorderPubmed
    cancer  
    promising novel strategy for sensitizing chemical therapy of cancers and increasing the chemotherapeutic efficacy through knockdown LAPTM4B-35 expression by RNAi
    cancerdigestivepancreas
    LAPTM4B-35 may represent a new molecular target for the clinical evaluation and treatment of pancreatic carcinoma
    ANIMAL & CELL MODELS