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CMTM5-v1, a four-transmembrane protein, presents a secreted form released via a vesicle-mediated secretory pathway

Henan Li1, Xiaohuan Guo, Luning Shao

  • 1Center for Human Disease Genomics, Department of Immunology, School of Basic Medical Sciences, Health Science Center, Peking University, 38 Xueyuan Road, Beijing 100191, China.

BMB Reports
|April 2, 2010
PubMed

Insights

This study reports the first evidence of a secreted form of CMTM5-v1, a protein involved in cell communication. This novel secretion pathway offers insights into vesicle-mediated transport mechanisms.

Area of Science:

  • Molecular Biology
  • Cell Biology
  • Biochemistry

Background:

  • The CKLF-like MARVEL transmembrane domain-containing (CMTM) family links chemokines and TM4SF proteins.
  • Previous research identified secreted forms of CMTM1 and CMTM2.
  • CMTM5-v1 is the primary RNA splicing variant of CMTM5.

Purpose of the Study:

  • To characterize the secreted form of CMTM5-v1.
  • To investigate the secretion pathway of CMTM5-v1.
  • To explore the implications for vesicle-mediated secretion research.

Main Methods:

  • Sucrose gradient ultracentrifugation to determine vesicle density.
  • Immunofluorescence microscopy to assess co-localization with markers (CD63, Golgi).
  • Pharmacological inhibition of secretion pathways using brefeldin A and wortmannin.

Main Results:

  • CMTM5-v1 is secreted in small vesicles (100 nm diameter) with a peak density of 1.19 g/ml.
  • CMTM5-v1 does not co-localize with CD63 or the Golgi complex.
  • Secretion of CMTM5-v1 is inhibited by brefeldin A but not wortmannin.

Conclusions:

  • CMTM5-v1 is secreted via a distinct vesicle-mediated pathway.
  • This finding contributes to understanding MARVEL domain protein secretion.
  • The study opens new avenues for research into unconventional secretory mechanisms.

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