Alteration of fibronectin receptors (integrins) in phorbol ester-treated human promonocytic leukemia cells.

Alteration of Fibronectin Receptors (Integrins) in Phorbol Ester-treated Human Promonocytic Leukemia Cells1

We describe the isolation of human fibronectin receptors (integrins) from two nonadherent promonocytic cell lines and from peripheral blood monocytes. Integrins purified from U-937 and THP-1 cells exhibited identical electrophoretic migrations on sodium dodecyl sulfate gels run under reducing (~M, 150,000) and nonreducing (a, M, 160,000; /S, M, 130,000) conditions. Treatment of U-937 or THP-1 c...

Phorbol Ester-Induced Promyelocytic Leukemia Cell Adhesion to Marrow Stromal Cells Involves Fibronectin Specific a5(31 Integrin Receptors

Hyposialylation of integrins stimulates the activity of myeloid fibronectin receptors.

Despite numerous reports suggesting that beta(1) integrin receptors undergo differential glycosylation, the potential role of N-linked carbohydrates in modulating integrin function has been largely ignored. In the present study, we find that beta(1) integrins are differentially glycosylated during phorbol ester (PMA)-stimulated differentiation of myeloid cells along the monocyte/macrophage line...

Phorbol ester modulation of integrin-mediated cell adhesion: a postreceptor event

Chinese hamster ovary (CHO) suspension culture cells adhere readily to substrata coated with extracellular matrix proteins such as fibronectin, vitronectin, or laminin. In the case of fibronectin, it is known that adhesion is mediated by an integrin-type, cell surface fibronectin receptor (FnR). We demonstrate here that treatment of CHO cells with submicromolar concentrations of phorbol ester p...

Prevention of phorbol ester receptor down modulation in human myeloblastic leukemia ML-1 cells by differentiation-stimulating serum components.

The phorbol esters 12-O-tetradecanoylphorbol-13-acetate, phorbol 12,13-didecanoate, phorbol 12,13-dibutyrate (PDB), and phorbol 12,13-dibenzoate were found to compete with [20-3H]-PDB binding to human myeloblastic leukemia ML-1 cells in approximate proportion to their differentiation-inducing capacity. Fetal bovine serum decreased the down modulation of phorbol ester receptor sites on these cel...