Expression of chondroitin sulfate as a unique type of proteoglycan on the cell membrane of multipotential and committed hemopoietic progenitor cells.
Proteoglycans are increasingly implicated as a major factor in the regulation of hemopoiesis. They are generally synthesized by stromal cells and released to the extracellular matrix. More recently the ability of hemopoietic progenitor cells to synthesize proteoglycans has come into focus. In the present study we maintained 3 cloned factor-dependent hemopoietic progenitor cells (B6 and F-mix which are multipotential and F-2 which is bipotential) in liquid culture. The cells were pulse-labeled with 35SO4 which becomes incorporated into the glycan side-chains of proteoglycans. We then studied subcellular distribution and chemical characterization of the newly synthesized proteoglycans. All 3 cell lines synthesized chondroitin sulfate as a unique type of proteoglycan as identified by gel filtration on a Sepharose CL-4B column followed by chondroitinase ABC cleavage of its glycosaminoglycan. This single type of proteoglycan was compartmentalized into intracellular, membrane-associated and extracellular pools. Its density on the membrane appeared to be a function of the differentiation state of the cell. The functional significance of membrane-associated proteoglycan in hemopoietic progenitor cells appears to be underestimated and requires further investigation.
Shirota
T
T
University of Mississippi School of Medicine, Jackson.
Minguell
J J
JJ
Tavassoli
M
M
D000818:Animals; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism*; D002809:Chondroitin Sulfates / Q000096:biosynthesis*; D002850:Chromatography, Gel; D006412:Hematopoietic Stem Cells / Q000378:metabolism* / Q000648:ultrastructure; D051379:Mice; D011509:Proteoglycans / Q000096:biosynthesis*
D011509:Proteoglycans; D002809:Chondroitin Sulfates