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Actin-binding protein-1 interacts with WASp-interacting protein to regulate growth factor-induced dorsal ruffle formation.

Cortesio CL, Perrin BJ, Bennin DA, Huttenlocher A - Mol. Biol. Cell (2009)

Bottom Line: Despite their structural similarity, we find that mAbp1 and cortactin have nonredundant functions in the regulation of dorsal ruffle formation. mAbp1, like cortactin, is a calpain 2 substrate and the preferred cleavage site occurs between the actin-binding domain and the proline-rich region, generating a C-terminal mAbp1 fragment that inhibits dorsal ruffle formation.Finally, we demonstrate that the interaction between mAbp1 and WIP is important in regulating dorsal ruffle formation and that WIP-mediated effects on dorsal ruffle formation require mAbp1.Taken together, these findings identify a novel role for mAbp1 in growth factor-induced dorsal ruffle formation through its interaction with WIP.

View Article: PubMed Central - PubMed

Affiliation: Department of Biomolecular Chemistry, University of Wisconsin, Madison, WI 53706, USA.

ABSTRACT
Growth factor stimulation induces the formation of dynamic actin structures known as dorsal ruffles. Mammalian actin-binding protein-1 (mAbp1) is an actin-binding protein that has been implicated in regulating clathrin-mediated endocytosis; however, a role for mAbp1 in regulating the dynamics of growth factor-induced actin-based structures has not been defined. Here we show that mAbp1 localizes to dorsal ruffles and is necessary for platelet-derived growth factor (PDGF)-mediated dorsal ruffle formation. Despite their structural similarity, we find that mAbp1 and cortactin have nonredundant functions in the regulation of dorsal ruffle formation. mAbp1, like cortactin, is a calpain 2 substrate and the preferred cleavage site occurs between the actin-binding domain and the proline-rich region, generating a C-terminal mAbp1 fragment that inhibits dorsal ruffle formation. Furthermore, mAbp1 directly interacts with the actin regulatory protein WASp-interacting protein (WIP) through its SH3 domain. Finally, we demonstrate that the interaction between mAbp1 and WIP is important in regulating dorsal ruffle formation and that WIP-mediated effects on dorsal ruffle formation require mAbp1. Taken together, these findings identify a novel role for mAbp1 in growth factor-induced dorsal ruffle formation through its interaction with WIP.

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mAbp1 localizes to PDGF-induced dorsal ruffles in fibroblast cells. NIH-3T3 cells were cultured on FN-coated coverslips, serum-starved, and stimulated with vehicle control or PDGF. Cells were fixed and stained with (A) rhodamine phalloidin and anti-mAbp1 antibody or (B) rhodamine phalloidin and anti-cortactin antibody. Bar, 10 μm.
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Figure 1: mAbp1 localizes to PDGF-induced dorsal ruffles in fibroblast cells. NIH-3T3 cells were cultured on FN-coated coverslips, serum-starved, and stimulated with vehicle control or PDGF. Cells were fixed and stained with (A) rhodamine phalloidin and anti-mAbp1 antibody or (B) rhodamine phalloidin and anti-cortactin antibody. Bar, 10 μm.

Mentions: Growth factor stimulation induces the formation of dynamic and transient circular ruffles on the dorsal surface of NIH-3T3 cells (Mellstrom et al., 1988). To determine if mAbp1 localizes to PDGF-induced circular dorsal ruffles, we generated a polyclonal antibody to mouse Abp1 to detect endogenous mAbp1. In serum-starved NIH-3T3 cells mAbp1 localized both to the peri-nuclear region and the cell periphery. Treatment of the serum-starved cells with PDGF induced dynamic actin remodeling into circular ring shaped structures on the dorsal surface of the cell. We found that endogenous mAbp1 colocalized with actin at PDGF-induced dorsal ruffles (Figure 1A). In accordance with previous reports (Krueger et al., 2003), we also found that cortactin localized with actin at PDGF-induced dorsal ruffles (Figure 1B). Together, these findings identify mAbp1 as a novel component of PDGF-induced dorsal ruffles.


Actin-binding protein-1 interacts with WASp-interacting protein to regulate growth factor-induced dorsal ruffle formation.

Cortesio CL, Perrin BJ, Bennin DA, Huttenlocher A - Mol. Biol. Cell (2009)

mAbp1 localizes to PDGF-induced dorsal ruffles in fibroblast cells. NIH-3T3 cells were cultured on FN-coated coverslips, serum-starved, and stimulated with vehicle control or PDGF. Cells were fixed and stained with (A) rhodamine phalloidin and anti-mAbp1 antibody or (B) rhodamine phalloidin and anti-cortactin antibody. Bar, 10 μm.
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Related In: Results  -  Collection

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Figure 1: mAbp1 localizes to PDGF-induced dorsal ruffles in fibroblast cells. NIH-3T3 cells were cultured on FN-coated coverslips, serum-starved, and stimulated with vehicle control or PDGF. Cells were fixed and stained with (A) rhodamine phalloidin and anti-mAbp1 antibody or (B) rhodamine phalloidin and anti-cortactin antibody. Bar, 10 μm.
Mentions: Growth factor stimulation induces the formation of dynamic and transient circular ruffles on the dorsal surface of NIH-3T3 cells (Mellstrom et al., 1988). To determine if mAbp1 localizes to PDGF-induced circular dorsal ruffles, we generated a polyclonal antibody to mouse Abp1 to detect endogenous mAbp1. In serum-starved NIH-3T3 cells mAbp1 localized both to the peri-nuclear region and the cell periphery. Treatment of the serum-starved cells with PDGF induced dynamic actin remodeling into circular ring shaped structures on the dorsal surface of the cell. We found that endogenous mAbp1 colocalized with actin at PDGF-induced dorsal ruffles (Figure 1A). In accordance with previous reports (Krueger et al., 2003), we also found that cortactin localized with actin at PDGF-induced dorsal ruffles (Figure 1B). Together, these findings identify mAbp1 as a novel component of PDGF-induced dorsal ruffles.

Bottom Line: Despite their structural similarity, we find that mAbp1 and cortactin have nonredundant functions in the regulation of dorsal ruffle formation. mAbp1, like cortactin, is a calpain 2 substrate and the preferred cleavage site occurs between the actin-binding domain and the proline-rich region, generating a C-terminal mAbp1 fragment that inhibits dorsal ruffle formation.Finally, we demonstrate that the interaction between mAbp1 and WIP is important in regulating dorsal ruffle formation and that WIP-mediated effects on dorsal ruffle formation require mAbp1.Taken together, these findings identify a novel role for mAbp1 in growth factor-induced dorsal ruffle formation through its interaction with WIP.

View Article: PubMed Central - PubMed

Affiliation: Department of Biomolecular Chemistry, University of Wisconsin, Madison, WI 53706, USA.

ABSTRACT
Growth factor stimulation induces the formation of dynamic actin structures known as dorsal ruffles. Mammalian actin-binding protein-1 (mAbp1) is an actin-binding protein that has been implicated in regulating clathrin-mediated endocytosis; however, a role for mAbp1 in regulating the dynamics of growth factor-induced actin-based structures has not been defined. Here we show that mAbp1 localizes to dorsal ruffles and is necessary for platelet-derived growth factor (PDGF)-mediated dorsal ruffle formation. Despite their structural similarity, we find that mAbp1 and cortactin have nonredundant functions in the regulation of dorsal ruffle formation. mAbp1, like cortactin, is a calpain 2 substrate and the preferred cleavage site occurs between the actin-binding domain and the proline-rich region, generating a C-terminal mAbp1 fragment that inhibits dorsal ruffle formation. Furthermore, mAbp1 directly interacts with the actin regulatory protein WASp-interacting protein (WIP) through its SH3 domain. Finally, we demonstrate that the interaction between mAbp1 and WIP is important in regulating dorsal ruffle formation and that WIP-mediated effects on dorsal ruffle formation require mAbp1. Taken together, these findings identify a novel role for mAbp1 in growth factor-induced dorsal ruffle formation through its interaction with WIP.

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