An alternative splice form of CMTM8 induces apoptosis

Int J Biochem Cell Biol. 2007;39(11):2107-19. doi: 10.1016/j.biocel.2007.06.002. Epub 2007 Jun 24.

Abstract

Previous studies have demonstrated that the chemokine-like factor (CKLF)-like MARVEL transmembrane domain containing 8 (CMTM8) protein accelerates the ligand-induced clearance of epidermal growth factor receptor (EGFR) from the cell surface. The absence of EGFR-mediated signaling induces cells to undergo apoptosis via caspase-dependent and -independent pathways. Here we report the cloning and sequencing of an alternative splice form of CMTM8, obtained from a human blood cDNA library, that utilizes apoptotic pathways distinct from CMTM8. The alternative splice variant arises from a deletion of exon 2 that prevents the expression of a full-length MARVEL domain, and cytosolic YXXPhi motifs. Nevertheless, CMTM8-v2 maintains the ability to induce apoptosis via caspase-dependent and -independent pathways to inhibit cell growth and colony formation. CMTM8 and CMTM8-v2 display different expression profiles and distinct subcellular localization patterns, while operating via different mechanisms to induce apoptosis. CMTM8-v2 did not affect EGFR internalization, implying that the MARVEL domain and/or the cytosolic YXXPhi motifs are necessary for CMTM8 to accelerate ligand-induced EGFR internalization.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alternative Splicing / genetics*
  • Apoptosis / genetics*
  • Apoptosis Inducing Factor / metabolism
  • Base Sequence
  • Caspases / metabolism
  • Cell Line
  • Cell Proliferation
  • Chemokines / chemistry
  • Chemokines / genetics*
  • Cytochromes / metabolism
  • DNA, Complementary / genetics
  • Endocytosis
  • Enzyme Activation
  • ErbB Receptors / metabolism
  • Gene Expression
  • Humans
  • MARVEL Domain-Containing Proteins
  • Membrane Potential, Mitochondrial
  • Molecular Sequence Data
  • Protein Structure, Tertiary
  • Protein Transport
  • Subcellular Fractions / metabolism
  • Transfection
  • bcl-2-Associated X Protein / metabolism

Substances

  • Apoptosis Inducing Factor
  • CMTM8 protein, human
  • Chemokines
  • Cytochromes
  • DNA, Complementary
  • MARVEL Domain-Containing Proteins
  • bcl-2-Associated X Protein
  • ErbB Receptors
  • Caspases