Molecular Biology Reports

, Volume 39, Issue 9, pp 8883–8889 | Cite as

TM7SF1 (GPR137B): a novel lysosome integral membrane protein

  • Jialin GaoEmail author
  • Libin Xia
  • Meiqing Lu
  • Binhua Zhang
  • Yueping Chen
  • Rang Xu
  • Lizhuo WangEmail author


In the previous proteomic study of human placenta, transmembrane 7 superfamily member 1 (TM7SF1) was found enriched in lysosome compartments. TM7SF1 encodes a 399-amino acid protein with a calculated molecular mass of 45 kDa. Bioinformatic analysis of its amino acid sequence showed that it is a multipass transmembrane protein containing a potential dileucine-based lysosomal targeting signal and four putative N-glycosylation sites. By percoll-gradient centrifugation and further subfraction ways, the lysosomal solute and membrane compartments were isolated respectively. Immunoblotting analysis indicated that TM7SF1 was co-fractioned with lysosome associated membrane protein 2 (LAMP2), which was only detected in lysosomal membrane compartments whereas not detected in the solute compartments. Using specific anti-TM7SF1 antibody and double-immunofluorescence with lysosome membrane protein LAMP1 and Lyso-Tracker Red, the colocalisations of endogenous TM7SF1 with lysosome and late endosome markers were demonstrated. All of this indicated that TM7SF1 is an integral lysosome membrane protein. Rat ortholog of TM7SF1 was found to be strongly expressed in heart, liver, kidney and brain while not or low detected in other tissues. In summary, TM7SF1 was a lysosomal integral membrane protein that shows tissue-specific expression. As a G-protein-coupled receptor in lysosome membrane, TM7SF1 was predicted function as signal transduction across lysosome membrane.


Integral membrane Lysosome Subcellular location TM7SF1 Signal transduction 



This work was partially supported by Talents Foundation of Yijishan Hospital (YR201104).


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Copyright information

© Springer Science+Business Media B.V. 2012

Authors and Affiliations

  1. 1.Department of Endocrinology and Genetic MetabolismYijishan Hospital of Wannan Medical CollegeWuhuChina
  2. 2.Department of Biochemistry and Molecular BiologyWannan Medical CollegeWuhuChina
  3. 3.Department of Biochemistry and Molecular BiologyBasic Medical College, Shanghai Jiaotong University School of MedicineShanghaiChina

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