TY - JOUR
T1 - Phosphorylation and proteolytic modification of specific cytoskeletal proteins in human neutrophils stimulated by phorbol 12-myristate 13-acetate
AU - Pontremoli, S.
AU - Melloni, E.
AU - Michetti, M.
AU - Sparatore, B.
AU - Salamino, F.
AU - Sacco, O.
AU - Horecker, B. L.
PY - 1987
Y1 - 1987
N2 - Stimulation of intact human neutrophils with phorbol 12-myristate 13-acetate results in the selective phosphorylation of two cytoskeletal protein components with molecular masses of 20 and 48 kDa. After phosphorylation the 48-kDa protein is no longer recovered as a component of the cytoskeletal fraction but is present as a fully soluble phosphoprotein. Phosphorylation of the 20-kDa protein (probably myosin light chains) signals a proteolytic conversion, catalyzed by calpain, to a smaller species having a molecular mass of approximately 15 kDa. Phosphorylation of both the 48- and 20-kDa proteins is related to the conversion of protein kinase C, also catalyzed by calpain, to the soluble fully active form. Leupeptin, an inhibitor of calpain, blocks both the phosphorylation of the target proteins and the proteolytic modification of the 20-kDa polypeptide. Thus, phosphorylation of cytoskeletal proteins and signal-directed proteolysis appear to be related processes that follow stimulation of human neutrophils by phorbol esters. The resulting changes in cytoskeletal organization may be involved in the expression of some neutrophil functions, such as exocytosis of specific granules.
AB - Stimulation of intact human neutrophils with phorbol 12-myristate 13-acetate results in the selective phosphorylation of two cytoskeletal protein components with molecular masses of 20 and 48 kDa. After phosphorylation the 48-kDa protein is no longer recovered as a component of the cytoskeletal fraction but is present as a fully soluble phosphoprotein. Phosphorylation of the 20-kDa protein (probably myosin light chains) signals a proteolytic conversion, catalyzed by calpain, to a smaller species having a molecular mass of approximately 15 kDa. Phosphorylation of both the 48- and 20-kDa proteins is related to the conversion of protein kinase C, also catalyzed by calpain, to the soluble fully active form. Leupeptin, an inhibitor of calpain, blocks both the phosphorylation of the target proteins and the proteolytic modification of the 20-kDa polypeptide. Thus, phosphorylation of cytoskeletal proteins and signal-directed proteolysis appear to be related processes that follow stimulation of human neutrophils by phorbol esters. The resulting changes in cytoskeletal organization may be involved in the expression of some neutrophil functions, such as exocytosis of specific granules.
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U2 - 10.1073/pnas.84.11.3604
DO - 10.1073/pnas.84.11.3604
M3 - Article
C2 - 3473471
AN - SCOPUS:0023239520
VL - 84
SP - 3604
EP - 3608
JO - Proceedings of the National Academy of Sciences of the United States of America
JF - Proceedings of the National Academy of Sciences of the United States of America
SN - 0027-8424
IS - 11
ER -