The Expression of Myristoylated Alanine-Rich C-Kinase Substrate in Oligodendrocytes Is Developmentally Regulated

Abstract

Myristoylated alanine-rich C-kinase substrate (MARCKS), a major substrate of activated protein kinase C (PKC), is thought to be involved in PKC-mediated signal transduction events. In the present study, we have examined the expression of MARCKS in primary cultures of rat glial cells. Western blot analysis of different glial cell types (i.e., astrocytes, oligodendrocytes and microglia) revealed a relatively high level of MARCKS protein in oligodendrocytes. MARCKS protein and MARCKS mRNA levels in oligodendrocytes increased with time in culture, indicating a developmental regulation in MARCKS gene expression in differentiating oligodendrocytes. Immunocytochemical examination of developing oligodendrocytes indicated a strong labeling of MARCKS distributed both in the cell body and in the lacy network of processes. These findings, in concert with our previous observations on the role of PKC in oligodendrogenesis, strongly implicate a PKC-signaling system in oligodendrocyte development.

Quantitative temporal proteomic analysis of human embryonic stem cell differentiation into oligodendrocyte progenitor cells

“…The regulation of PI(4,5)P2 by MARCKS has been suggested to play a role in the outgrowth of membranous cellular processes in mature oligodendrocytes 32 . Previous studies have found that MARCKS mRNA levels increase as oligodendrocytes mature, suggesting developmental regulation of this protein 33 . However, there is limited information in the literature regarding the protein expression of MARCKS along oligodendrocyte differentiation.…”

Protein kinase C prevents oligodendrocyte differentiation: modulation of actin cytoskeleton and cognate polarized membrane traffic

“…The importance of the cytoskeleton in oligodendrocyte process outgrowth is readily appreciated since CNP and myelin-associated glycoprotein (MAG), both playing crucial roles in the biogenesis of the myelin sheath, are associated with the actin cytoskeleton (Wilson and Brophy, 1989;Trapp et al, 1989;De Angelis and Braun, 1996). Furthermore, a developmental expression of cytoskeletal proteins and cytoskeleton-related proteins, including MARCKS, has been described (Raff et al, 1984;Vouyiouklis and Brophy, 1993;Léna et al, 1994;Gallo and Armstrong, 1995;Bhat et al, 1995). Hence, extensive cytoskeletal remodeling is needed at the onset of oligodendrocyte differentiation.…”

Protein kinase C and mitogen‐activated protein kinase signalling in oligodendrocytes

“…As mentioned above, downstream substrates of PKC in OL include MARCKS, c-fos, and ERK. It has been noted that PMA-treatment of progenitor OL can cause phosphorylation of the MARCKS protein, and that the MARCKS protein can be associated with the cytoplasm as well as the processes of OL (Bhat, 1991;Bhat et al, 1995). While these results strongly suggest a relationship between PMA-induced MARCKS phosphorylation and progenitor OL proliferation, a definitive link has yet to be established (Bhat, 1991;Deloulme et al, 1992).…”

“…Signals stemming from PKC activation in OL can lead to the phosphorylation of ERKs and the myristoylated alanine-rich C-kinase substrate (MARCKS) ( Baron et al, 1999;Bhat, 1991;Bhat et al, 1995;Stariha et al, 1997). PKC can also transduce signals to the nucleus in OL, activating transcription of genes such as c-fos (Bhat et al, 1992).…”