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Phosphorylation of cytoskeleton‐associated proteins, pp58 and pp60, in tumouricidal murine peritoneal macrophages
Author(s) -
Didier ES,
Fan S,
Wheeler E,
Tompkins WAF
Publication year - 1989
Publication title -
immunology and cell biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.999
H-Index - 104
eISSN - 1440-1711
pISSN - 0818-9641
DOI - 10.1038/icb.1989.46
Subject(s) - phosphorylation , lipopolysaccharide , incubation , macrophage , microbiology and biotechnology , phorbol , protein phosphorylation , in vitro , chemistry , biology , biochemistry , protein kinase c , endocrinology , protein kinase a
Summary Two highly phosphorylated vimentin‐like proteins, pp58 and pp60, are expressed in macrophages activated in vivo to tumouricidal activity. Resident and elicited, non‐tumouricidal peritoneal macrophages displayed low and intermediate levels of phosphorylated pp58 and pp60, respectively. C3H/HeN macrophages became tumouricidal after incubation with 0middot;1 μg/mL A23187 plus 10 nmol/L 12‐phorbol 13‐myristate acetate (PMA), or 0·1 μg/mL A23187 plus 100 ng/mL lipopolysaccharide (LPS), and displayed increased phosphorylation of pp58 and pp60. LPS non‐responder C3H/HeJ macrophages were not tumouricidal nor did they show increased phosphorylation of pp58 and pp60 after incubation with LPS plus A23187 in vitro . C3H/HeJ macrophages, however, did become tumouricidal and expressed increased phosphorylation or pp58 and pp60 after incubation with A23187 and PMA. Addition of PGE 2 (10 ‐8 mol/L), resulted in down‐regulation of macrophage tumouricidal activity and decreased pp58 and pp60 phosphorylation, which was reversed by addition of indomethacin (10 ‐6 mol/L) to cultures with PGE 2 . Phosphorylation increased within 5 min after adding activating stimuli while incorporation of [ 35 S]‐methionine into a 58 kD protein did not occur until 6 h later. No 60 kD protein synthesis was detected during the first 8 h after adding activating stimuli, indicating that previously synthesized proteins were phosphorylated during macrophage activation. These results signify a physiological role for the phosphorylation of cytoskeleton‐associated pp58 and pp60 during macrophage activation to tumour cytotoxicity.