Packing density of the erythropoietin receptor transmembrane domain correlates with amplification of biological responses.
The formation of signal-promoting dimeric or oligomeric receptor complexes at the cell surface is modulated by self-interaction of their transmembrane (TM) domains. To address the importance of TM domain packing density for receptor functionality, we examined a set of asparagine mutants in the TM domain of the erythropoietin receptor (EpoR). We identified EpoR-T242N as a receptor variant that is present at the cell surface similar to wild-type EpoR but lacks visible localization in vesicle-like structures and is impaired in efficient activation of specific signaling cascades. Analysis by a molecular modeling approach indicated an increased interhelical distance for the EpoR-T242N TM dimer. By employing the model, we designed additional mutants with increased or decreased packing volume and confirmed a correlation between packing volume and biological responsiveness. These results propose that the packing density of the TM domain provides a novel layer for fine-tuned regulation of signal transduction and cellular decisions.
Division Systems Biology of Signal Transduction, DKFZ-ZMBH Alliance, German Cancer Research Center, Heidelberg, Germany.
Verena
V
Becker
Durba
D
Sengupta
Robin
R
Ketteler
G Matthias
GM
Ullmann
Jeremy C
JC
Smith
Ursula
U
Klingmüller
D000818:Animals; D001216:Asparagine / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D001665:Binding Sites; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism*; D049109:Cell Proliferation; D019281:Dimerization; D005434:Flow Cytometry; D015151:Immunoblotting; D047468:Immunoprecipitation; D051379:Mice; D008856:Microscopy, Fluorescence; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism; D009154:Mutation; D041681:NIH 3T3 Cells; D017434:Protein Structure, Tertiary; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D017467:Receptors, Erythropoietin / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction / Q000235:genetics / Q000502:physiology
D017467:Receptors, Erythropoietin; D001216:Asparagine; D051057:Proto-Oncogene Proteins c-akt; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3