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SMIM1 is a type II transmembrane phosphoprotein and displays the Vel blood group antigen at its carboxyl‐terminus
Author(s) -
Arnaud Lionel,
Kelley Liam P.,
Helias Virginie,
Cartron Jean-Pierre,
Ballif Bryan A.
Publication year - 2015
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/j.febslet.2015.09.029
Subject(s) - phosphoprotein , antigen , chemistry , transmembrane protein , microbiology and biotechnology , flow cytometry , phosphorylation , transmembrane domain , extracellular , amino acid , biochemistry , biology , immunology , receptor
Disruption of SMIM1, encoding small integral membrane protein 1, is responsible for the Vel‐negative blood type, a rare but clinically‐important blood type. However, the exact nature of the Vel antigen and how it is presented by SMIM1 are poorly understood. Using mass spectrometry we found several sites of phosphorylation in the N‐terminal region of SMIM1 and we found the initiating methionine of SMIM1 to be acetylated. Flow cytometry analyses of human erythroleukemia cells expressing N‐ or C‐terminally Flag‐tagged SMIM1, several point mutants of SMIM1, and a chimeric molecule between Kell and SMIM1 demonstrated that SMIM1 carries the Vel antigen as a type II membrane protein with a predicted C‐terminal extracellular domain of only 3–12 amino acids.