Novel characteristics of a 33KDa protein (pp33) rapidly phosphorylated in IL3 dependent cells by stimulation with IL3.
We report the novel properties of a 33 KDa cellular protein rapidly phosphorylated by stimulation of growth by IL3 in IL3 dependent lines. Although pp33 is readily soluble in SDS, SDS-solubilised pp33 is insoluble in non-ionic detergents and is excluded from electrophoretic analysis (IEF, NEPHGE) employing such detergents. Native pp33 is not extracted by non-ionic detergents with or without cation chelation. pp33 is concentrated in a cell fraction containing endoplasmic reticulum where it is associated with a specific trypsin-sensitive degredative enzyme, active at 4 degrees. Its unusual characteristics and kinetics of phosphorylation suggest pp33 may be a novel molecule, explain its absence in studies elsewhere where non-ionic detergent extraction has been exclusively used and suggest it is intimately related to the signal transduced by IL3.
Garland
J M
JM
Dept. Cell & Structural Biology, University of Manchester, U.K.
Ferris
D K
DK
Farrar
W L
WL
D000596:Amino Acids / Q000032:analysis; D000818:Animals; D002460:Cell Line; D015180:Electrophoresis, Gel, Two-Dimensional; D004591:Electrophoresis, Polyacrylamide Gel; D007377:Interleukin-3 / Q000494:pharmacology*; D051379:Mice; D008970:Molecular Weight; D010766:Phosphorylation; D011506:Proteins / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects; D013268:Stimulation, Chemical
D000596:Amino Acids; D007377:Interleukin-3; D011506:Proteins