Packing Density of the Erythropoietin Receptor Transmembrane Domain Correlates with Amplification of Biological Responses.
11771 - 11782.
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.
|Title:||Packing Density of the Erythropoietin Receptor Transmembrane Domain Correlates with Amplification of Biological Responses|
|Keywords:||PRIMARY FAMILIAL POLYCYTHEMIA, SIGNAL-TRANSDUCTION, MEMBRANE-PROTEINS, PROGENITOR CELLS, POINT MUTATION, DIMERIZATION, ACTIVATION, OLIGOMERIZATION, GENE, ERYTHROCYTOSIS|
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