Changes in protein sulfation in human erythroleukemia (HEL), CHRF-288-11, and K562 cells following treatment with dimethyl sulfoxide or phorbol 12-myristate 13-acetate.

This study has demonstrated that three hematopoietic tumor cell lines with megakaryocytic characteristics, HEL, CHRF-288-11, and K562, synthesize a number of sulfated proteins. The major HEL sulfated proteins were a doublet at 88 and 92 kDa and several closely spaced bands between 125 and 160 kDa and more acidic proteins of 210 kDa. Treatment with dimethylsulfoxide (DMSO) for 24 h almost completely inhibited labeling of sulfated proteins, and up to 48 h, labeling was found almost entirely in a band at 125 kDa. Treatment with phorbol 12-myristate 13-acetate (PMA) nearly eliminated labeling of the 88- and 92-kDa bands and resulted in the appearance of a large amount of labeling between 96 and 108 kDa. Sulfated proteins of 135 and 210 kDa were immunoprecipitated by an antibody against platelet GP Ib. A 130-kDa protein was immunoprecipitated by an antibody against the beta-1 integrin subunit. The major proteins labeled in CHRF cells were at 68, 90, 98, 125, and 148 kDa. Treatment with PMA greatly reduced the labeling of the 148-kDa band, eliminated the labeling of the 68-kDa band, and markedly enhanced labeling of the 92-kDa region. The major proteins labeled in K562 cells were at 110, 120-130, and 145 kDa. PMA reduced the labeling of the 110- and 145-kDa proteins and extensively increased labeling of bands at 120-130, 78, and 84 kDa, and DMSO caused decreased labeling of the 120- to 130-kDa proteins. This is the first demonstration of sulfation of specific proteins in hematopoietic cell lines and of the alteration of sulfation of specific proteins in any cells in response to treatment with differentiation-inducing agents. We hypothesize that changes in sulfation of proteins may be relevant to the maturation or malignant growth of megakaryocytic cells.