F. Nakamura et al., PHOSPHORYLATION OF T-558 OF MOESIN DETECTED BY SITE-SPECIFIC ANTIBODIES IN RAW264.7 MACROPHAGES, Biochemical and biophysical research communications, 226(3), 1996, pp. 650-656
To determine, whether (558)Thr in the carboxyl-terminal domain of moes
in is phosphorylated in cells other than platelets, rabbit phosphoryla
tion state-specific antibodies were made to the chemically phosphoryla
ted synthetic hexapeptide KYKpTLR of the moesin sequence, as well as t
o the unphosphorylated form. The affinity-purified antibody population
s were specific for either the phosphorylated or the unmodified peptid
e conjugated to BSA. Site-specific phosphorylation of moesin is detect
ed in RAW macrophages by Western blot analysis, and immunofluorescence
studies demonstrate that phosphorylated moesin is localized in filopo
dial protrusions. After pretreatment with the phosphatase inhibitor ca
lyculin A, a similar effect to that seen in platelets is found, namely
a substantial increase in moesin phosphorylation at (558)Thr and redi
stribution of phospho-moesin together with F-actin into one or more ri
ng-like structures in the cytoplasm, presumably due to binding of phos
phorylated moesin to F-actin. (C) 1996 Academic Press, Inc.