The proline‐rich protein palladin is a binding partner for profilin

Abstract

Palladin is an actin‐associated protein that has been suggested to play critical roles in establishing cell morphology and maintaining cytoskeletal organization in a wide variety of cell types. Palladin has been shown previously to bind directly to three different actin‐binding proteins vasodilator‐stimulated phosphoprotein (VASP), α‐actinin and ezrin, suggesting that it functions as an organizing unit that recruits actin‐regulatory proteins to specific subcellular sites. Palladin contains sequences resembling a motif known to bind profilin. Here, we demonstrate that palladin is a binding partner for profilin, interacting with profilin via a poly proline‐containing sequence in the amino‐terminal half of palladin. Double‐label immunofluorescence staining shows that palladin and profilin partially colocalize in actin‐rich structures in cultured astrocytes. Our results suggest that palladin may play an important role in recruiting profilin to sites of actin dynamics.

Palladin is overexpressed in the non-neoplastic stroma of infiltrating ductal adenocarcinomas of the pancreas, but is only rarely overexpressed in neoplastic cells

“…21,22 The palladin protein binds a number of actin-binding proteins including profillin, alpha-actinin, ezrin and vasodilator-stimulated phosphoprotein [VASP]. 2,3,12,[17][18][19][20] Palladin is therefore believed to play an important role in recruiting these other proteins to sites of actin dynamics, thereby functioning in cytoskeletal formation, cell movement and cell-extracellular matrix interactions. 2,3,12,[17][18][19][20] It should therefore not be surprising that actin filaments, and therefore palladin proteins, are important in fibroblast function and are overexpressed in fibroblasts in desmoplastic stroma.…”

“…3,12,[17][18][19][20] Palladin is a well-documented microfilament associated protein, where it is co-localizes with alpha-actinin in a "beads on a string" pattern along f-actin stress fibers. 21,22 The palladin protein binds a number of actin-binding proteins including profillin, alpha-actinin, ezrin and vasodilator-stimulated phosphoprotein [VASP].…”

The Association of Cortactin with Profilin-1 Is Critical for Smooth Muscle Contraction

“…Pfn-1 is able to interact with proline-rich domain-containing ligands such as palladin (39). The N-terminal and C-terminal helices of Pfn-1 form a binding cleft for poly-L-proline (26).…”

“…The sequence of this peptide contains Tyr-421 and adjacent residues, which are able to compete with endogenous cortactin for Pfn-1 binding (26,39). We used co-immunoprecipitation analysis to evaluate the effects of CTTN-I peptide on the protein/protein interaction.…”

Differential Quantitative Proteomics of Human Microvascular Endothelial Cells 1 by iTRAQ Reveals Palladin to be a New Biomarker During TGF-?1 Induced Endothelial Mesenchymal Transition

“…Palladin is a multi-domain, actin-binding protein which binds directly to F-actin and many other actin-binding proteins, including profilin, VASP, ezrin, Lasp-1, EPS8, CLP-36, α-actinin and ArgBP2 [30][31][32][33][34][35][36][37]. Palladin is a cytoskeletal protein that controls stress fiber integrity, and is expressed in epithelial and mesenchymal cells [38,39].…”