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Effects of tunicamycin on the expression and function of formyl peptide chemotactic receptors of differentiated HL-60 cells

Journal Article · · J. Immunol.; (United States)
OSTI ID:5783758

The authors' have shown previously that formyl peptide chemotactic receptors (FPCR) of human phagocytic cells contain at least two asparagine-linked oligosaccharide chains located at the distal end of the receptor. The requirement of these N-linked oligosaccharide chains for expression and function of FPCR was investigated in HL-60 cells induced to differentiate by N/sup 6/,O/sup 2/-dibutyryladenosine 3',5'-monophosphate (Bt/sub 2/cAMP) in the presence or absence of 5 ..mu..g/ml tunicamycin. Tunicamycin did not prevent the changes in morphology associated with Bt/sub 2/cAMP-induced differentiation of HL-60 cells. Autoradiographic analysis after SDS-PAGE of FPCR affinity labeled with N-formyl-Nle-Leu-Phe-Nle-(/sup 125/I) iodo-Tyr-Lys (formyl /sup 125/I-hexapeptide) and ethylene glycol bis(succinimidyl succinate) demonstrated that greater than 95% of FPCR expressed by tunicamycin-treated cells completely lacked N-linked oligosaccharide (M/sub r/ 32,000), and no fully glycosylated FPCR (M/sub r/ 62,000 to 85,000) was detectable. Scatchard analysis of formyl /sup 125/I-hexapeptide binding indicated the presence of two classes of binding sites for both control and tunicamycin-treated cells. Both control and tunicamuycin-treated cells augmented superoxide anion release, exhibited a migratory response, and showed a transient rise in intracellular free Ca/sup 2 +/ upon stimulation with N-formyl-Nle-Leu-Phe. However, the responses of the tunicamycin-treated cells were less than that of the control cells.

Research Organization:
Yale Univ., New Haven, CT
OSTI ID:
5783758
Journal Information:
J. Immunol.; (United States), Journal Name: J. Immunol.; (United States) Vol. 136; ISSN JOIMA
Country of Publication:
United States
Language:
English