MARCKS is a downstream effector in platelet-derived growth factor-induced cell motility in activated human hepatic stellate cells.
Myristoylated alanine-rich protein kinase c substrate (MARCKS) has been suggested to be implicated in cell adhesion, secretion, motility and mitogenesis through regulation of the actin cytoskeletal structure. In the present study, a possible link between MARCKS and the platelet-derived growth factor (PDGF) signaling pathway was investigated in activated human hepatic stellate cells (hHSC), critical regulators of hepatic fibrogenesis. PDGF-BB stimulation resulted in a bi-directional movement of MARCKS that coincided with the phosphorylation of MARCKS and the activation of both PKCepsilon and PKCalpha. Biochemical inhibition of PKC kinase activity and small interfering RNA (siRNA) against PKCepsilon demonstrated that PKCepsilon is indispensable for PDGF-BB-induced MARCKS phosphorylation and cell migration. Immunoprecipitation studies revealed an association between MARCKS and the PDGFbeta-receptor, while the PDGFbeta-receptor and PKCalpha associated with focal adhesion kinase (FAK). Transient transfection with MARCKS DNA plasmid remarkably reduced PDGF-BB stimulated cell motility. In contrast, siRNA against MARCKS increased cell migration in RNAi treated cells in comparison to the scrambled control cells. In conclusion, the present study indicates that MARCKS play a major key role in PDGF-BB-induced chemotaxis in activated hHSC.
Rombouts
Krista
K
Department of Internal Medicine, University of Florence, Italy. k.rombouts@dmi.unifi.it
Lottini
Benedetta
B
Caligiuri
Alessandra
A
Liotta
Francesco
F
Mello
Tommaso
T
Carloni
Vinicio
V
Marra
Fabio
F
Pinzani
Massimo
M
D000077214:Becaplermin; D002465:Cell Movement / Q000187:drug effects*; D002478:Cells, Cultured; D002633:Chemotaxis / Q000187:drug effects; D004789:Enzyme Activation / Q000187:drug effects; D051416:Focal Adhesion Protein-Tyrosine Kinases / Q000378:metabolism; D022781:Hepatocytes / Q000166:cytology / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism*; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism*; D042541:Intracellular Space / Q000187:drug effects / Q000378:metabolism; D007527:Isoenzymes / Q000378:metabolism; D008565:Membrane Proteins / Q000378:metabolism*; D008954:Models, Biological; D000076250:Myristoylated Alanine-Rich C Kinase Substrate; D010766:Phosphorylation / Q000187:drug effects; D010982:Platelet-Derived Growth Factor / Q000494:pharmacology*; D011485:Protein Binding / Q000187:drug effects; D051744:Protein Kinase C-epsilon / Q000378:metabolism; D021381:Protein Transport / Q000187:drug effects; D020574:Proto-Oncogene Proteins c-sis; D017479:Receptors, Platelet-Derived Growth Factor / Q000378:metabolism; D055672:Static Electricity
D047908:Intracellular Signaling Peptides and Proteins; D007527:Isoenzymes; C000619710:MARCKS protein, human; D008565:Membrane Proteins; D010982:Platelet-Derived Growth Factor; D020574:Proto-Oncogene Proteins c-sis; D000076250:Myristoylated Alanine-Rich C Kinase Substrate; D000077214:Becaplermin; D017479:Receptors, Platelet-Derived Growth Factor; D051416:Focal Adhesion Protein-Tyrosine Kinases; D051744:Protein Kinase C-epsilon