α chain can be modified in post-transcriptional manner by alternative splicing creating different variant of mRNA. Splicing on 3´end produces transcript where 25 amino acids in C-terminal region are completely replaced by 35 new amino acids. Such protein is functional, but 10 times less abundant. Another splicing variant lacks both transmembrane and cytoplasmic domains. Remaining extracellular domain acts as a soluble GM-CSFRα and have been identified in bone marrow, monocytes and macrophages, placenta and chorio-carcinoma cells. Splicing products on the 5´end were found in primary haematopoietic cells and acute myeloid leukemia blasts.
