Interleukin 3-specific tyrosine phosphorylation of a membrane glycoprotein of Mr 150,000 in multi-factor-dependent myeloid cell lines.

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Abstract
Tyrosine phosphorylation of cellular proteins induced by various hematopoietic growth factors such as interleukin 3 (IL3), granulocyte‐macrophage colony‐stimulating factor (GM‐CSF) and interleukin 4 (IL4) was studied in several multi‐factor‐dependent myeloid cell lines. Among the growth factors, IL3 specifically induced rapid tyrosine phosphorylation of a membrane glycoprotein of mol. wt 150 kd (gpp150) in the IL3‐dependent cell lines, IC2 and DA‐1. The IL3‐induced tyrosine phosphorylation of gpp150 was detected within 30 s, reached a maximum at 3 min and decreased thereafter. The concentration of IL3 required for half‐maximum stimulation of gpp150 tyrosine phosphorylation with 2.5 x 10(6)/ml cells was approximately 200 pM, which is the same as the dissociation constant for 125I‐labeled IL3 binding. gpp150 was constitutively phosphorylated on tyrosine residue(s) in growth factor independent variants, IC2Tr and DA‐1Tr, derived from IC2 and DA‐1 respectively. Neither variant synthesized IL3. The present findings suggest that tyrosine phosphorylation of gpp150 is a critical event involved in both IL3‐dependent and ‐independent growth.