Actin modulation of a MARCKS phosphorylation site located outside the effector domain
Biochemical and Biophysical Research Communications. 2009-06-01; 383(3): 353-357
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Toledo A(1), Arruti C.
(1)Universidad de la República, Iguá, Montevideo, Uruguay.
MARCKS (Myristoylated alanine-rich C kinase substrate) is a ubiquitous actin
regulating protein, especially abundant in the nervous system. This protein may
be phosphorylated by other enzymes, particularly by proline-directed kinases, at
serine and threonine residues located at different sites along its chain. We
demonstrate here that the phosphorylation of chick MARCKS at serine 25, which
only takes place in the nervous tissue, does not impair its association with
particular plasma membrane regions such as the “detergent resistant microdomains”
that also contain actin. This phosphorylated form of MARCKS is able to bind
actin, and the integrity of actin filaments in cells (retina neuroblasts) is a
necessary condition to sustain this phosphorylation. Taken together, these
results indicate the existence of a functional interaction between actin
filaments and MARCKS in cells, and particularly of an action in maintaining a
phosphorylation in a region of the N-terminal moiety of MARCKS.