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Concerted regulation of focal adhesion dynamics by galectin-3 and tyrosine-phosphorylated caveolin-1.

Goetz JG, Joshi B, Lajoie P, Strugnell SS, Scudamore T, Kojic LD, Nabi IR - J. Cell Biol. (2008)

Bottom Line: Expression of the Mgat5/galectin lattice alone induces FAs and cell spreading.In human MDA-435 cancer cells, Cav1 expression, but not mutant Y14FCav1, stabilizes FAK exchange and stimulates de novo FA formation in protrusive cellular regions.Thus, transmembrane crosstalk between the galectin lattice and pY14Cav1 promotes FA turnover by stabilizing FAK within FAs defining previously unknown, interdependent roles for galectin-3 and pY14Cav1 in tumor cell migration.

View Article: PubMed Central - PubMed

Affiliation: Department of Cellular and Physiological Sciences, Life Sciences Institute, University of British Columbia, Vancouver, British Columbia, Canada.

ABSTRACT
Both tyrosine-phosphorylated caveolin-1 (pY14Cav1) and GlcNAc-transferase V (Mgat5) are linked with focal adhesions (FAs); however, their function in this context is unknown. Here, we show that galectin-3 binding to Mgat5-modified N-glycans functions together with pY14Cav1 to stabilize focal adhesion kinase (FAK) within FAs, and thereby promotes FA disassembly and turnover. Expression of the Mgat5/galectin lattice alone induces FAs and cell spreading. However, FAK stabilization in FAs also requires expression of pY14Cav1. In cells lacking the Mgat5/galectin lattice, pY14Cav1 is not sufficient to promote FAK stabilization, FA disassembly, and turnover. In human MDA-435 cancer cells, Cav1 expression, but not mutant Y14FCav1, stabilizes FAK exchange and stimulates de novo FA formation in protrusive cellular regions. Thus, transmembrane crosstalk between the galectin lattice and pY14Cav1 promotes FA turnover by stabilizing FAK within FAs defining previously unknown, interdependent roles for galectin-3 and pY14Cav1 in tumor cell migration.

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Gal-3 and Cav1 work in concert to generate intra-FA domains. (A) In Mgat5−/− cells lacking the Mgat5/galectin lattice, FAs are deficient and FAK is mostly cytosolic. (B) Gal-3-dependent integrin clustering promotes integrin activation as well as ligand-induced integrin activation (Lagana et al., 2006). Under serum-free conditions, expression of the Mgat5/galectin lattice alone can induce the formation of FAs and cell spreading (i.e., ESC-Rescue cells) but not FAK stabilization in FA domains. (C) Expression of pY14Cav1 results in the formation of an ordered membrane domain (Gaus et al., 2006) that results in the stabilization within the FA of integrin, FAK, and paxillin as well as, potentially, other FA components. Src-dependent FAK phosphorylation and its stable association with FAs lead to focal disassembly and turnover (Hamadi et al., 2005) and pY14Cav1 promotes FA disassembly such as observed in Cav1 transfected MDA-435 cells (Fig. 9). However, Gal-3/pY14Cav1-mediated stabilization of FAK in FAs is not sufficient to induce FA disassembly (Fig. 7). How domain organization occurs within the FA remains speculative and the concentration of integrin and FAK within an intra-FA liquid ordered domain is hypothetical. Indeed, the temporal and spatial nature of pY14Cav1 association with FAs remains to be determined.
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fig10: Gal-3 and Cav1 work in concert to generate intra-FA domains. (A) In Mgat5−/− cells lacking the Mgat5/galectin lattice, FAs are deficient and FAK is mostly cytosolic. (B) Gal-3-dependent integrin clustering promotes integrin activation as well as ligand-induced integrin activation (Lagana et al., 2006). Under serum-free conditions, expression of the Mgat5/galectin lattice alone can induce the formation of FAs and cell spreading (i.e., ESC-Rescue cells) but not FAK stabilization in FA domains. (C) Expression of pY14Cav1 results in the formation of an ordered membrane domain (Gaus et al., 2006) that results in the stabilization within the FA of integrin, FAK, and paxillin as well as, potentially, other FA components. Src-dependent FAK phosphorylation and its stable association with FAs lead to focal disassembly and turnover (Hamadi et al., 2005) and pY14Cav1 promotes FA disassembly such as observed in Cav1 transfected MDA-435 cells (Fig. 9). However, Gal-3/pY14Cav1-mediated stabilization of FAK in FAs is not sufficient to induce FA disassembly (Fig. 7). How domain organization occurs within the FA remains speculative and the concentration of integrin and FAK within an intra-FA liquid ordered domain is hypothetical. Indeed, the temporal and spatial nature of pY14Cav1 association with FAs remains to be determined.

Mentions: Our data supports a model in which Gal-3 binding promotes integrin clustering and formation of focal contacts (Fig. 10). Subsequent recruitment of pY14Cav1 will result in the formation of a stabilized domain within the FA that promotes the stabilized recruitment of FAK, paxillin, and other effectors of FA turnover. This domain is proposed to be equivalent to the ordered lipid domains in FAs previously described to be pY14Cav1 dependent (Gaus et al., 2006). Together with the established interaction of pY14Cav1 with integrins (Wary et al., 1998; Wei et al., 1999; Mettouchi et al., 2001; del Pozo et al., 2005; Radel and Rizzo, 2005), these data conclusively describe a role for pY14Cav1 in FA domain organization. However, it is important to recognize that evidence for a stable association of pY14Cav1 within FAs is based on the use of a single monoclonal antibody that crossreacts with phospho-paxillin (Hill et al., 2007). These data do not exclude a localization of pY14Cav1 to FAs, but do suggest that the exclusive FA distribution of pY14Cav1 based on antibody labeling may be exaggerated. In addition, the role for pY14Cav1 as an inhibitor of Src leading to Rho activation (Grande-Garcia et al., 2007) contrasts the critical role of Src kinase activity in phosphorylation of Cav1 and other FA components, such as FAK, leading to FA disassembly. As such, the formation of a stable pY14Cav1 containing domain within the FA, as proposed in Fig. 10, remains hypothetical and pY14Cav1-dependent regulation of FA domains may invoke the temporal and spatial recruitment of pY14Cav1 to FAs and mechanistic details that remain to be defined.


Concerted regulation of focal adhesion dynamics by galectin-3 and tyrosine-phosphorylated caveolin-1.

Goetz JG, Joshi B, Lajoie P, Strugnell SS, Scudamore T, Kojic LD, Nabi IR - J. Cell Biol. (2008)

Gal-3 and Cav1 work in concert to generate intra-FA domains. (A) In Mgat5−/− cells lacking the Mgat5/galectin lattice, FAs are deficient and FAK is mostly cytosolic. (B) Gal-3-dependent integrin clustering promotes integrin activation as well as ligand-induced integrin activation (Lagana et al., 2006). Under serum-free conditions, expression of the Mgat5/galectin lattice alone can induce the formation of FAs and cell spreading (i.e., ESC-Rescue cells) but not FAK stabilization in FA domains. (C) Expression of pY14Cav1 results in the formation of an ordered membrane domain (Gaus et al., 2006) that results in the stabilization within the FA of integrin, FAK, and paxillin as well as, potentially, other FA components. Src-dependent FAK phosphorylation and its stable association with FAs lead to focal disassembly and turnover (Hamadi et al., 2005) and pY14Cav1 promotes FA disassembly such as observed in Cav1 transfected MDA-435 cells (Fig. 9). However, Gal-3/pY14Cav1-mediated stabilization of FAK in FAs is not sufficient to induce FA disassembly (Fig. 7). How domain organization occurs within the FA remains speculative and the concentration of integrin and FAK within an intra-FA liquid ordered domain is hypothetical. Indeed, the temporal and spatial nature of pY14Cav1 association with FAs remains to be determined.
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Related In: Results  -  Collection

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fig10: Gal-3 and Cav1 work in concert to generate intra-FA domains. (A) In Mgat5−/− cells lacking the Mgat5/galectin lattice, FAs are deficient and FAK is mostly cytosolic. (B) Gal-3-dependent integrin clustering promotes integrin activation as well as ligand-induced integrin activation (Lagana et al., 2006). Under serum-free conditions, expression of the Mgat5/galectin lattice alone can induce the formation of FAs and cell spreading (i.e., ESC-Rescue cells) but not FAK stabilization in FA domains. (C) Expression of pY14Cav1 results in the formation of an ordered membrane domain (Gaus et al., 2006) that results in the stabilization within the FA of integrin, FAK, and paxillin as well as, potentially, other FA components. Src-dependent FAK phosphorylation and its stable association with FAs lead to focal disassembly and turnover (Hamadi et al., 2005) and pY14Cav1 promotes FA disassembly such as observed in Cav1 transfected MDA-435 cells (Fig. 9). However, Gal-3/pY14Cav1-mediated stabilization of FAK in FAs is not sufficient to induce FA disassembly (Fig. 7). How domain organization occurs within the FA remains speculative and the concentration of integrin and FAK within an intra-FA liquid ordered domain is hypothetical. Indeed, the temporal and spatial nature of pY14Cav1 association with FAs remains to be determined.
Mentions: Our data supports a model in which Gal-3 binding promotes integrin clustering and formation of focal contacts (Fig. 10). Subsequent recruitment of pY14Cav1 will result in the formation of a stabilized domain within the FA that promotes the stabilized recruitment of FAK, paxillin, and other effectors of FA turnover. This domain is proposed to be equivalent to the ordered lipid domains in FAs previously described to be pY14Cav1 dependent (Gaus et al., 2006). Together with the established interaction of pY14Cav1 with integrins (Wary et al., 1998; Wei et al., 1999; Mettouchi et al., 2001; del Pozo et al., 2005; Radel and Rizzo, 2005), these data conclusively describe a role for pY14Cav1 in FA domain organization. However, it is important to recognize that evidence for a stable association of pY14Cav1 within FAs is based on the use of a single monoclonal antibody that crossreacts with phospho-paxillin (Hill et al., 2007). These data do not exclude a localization of pY14Cav1 to FAs, but do suggest that the exclusive FA distribution of pY14Cav1 based on antibody labeling may be exaggerated. In addition, the role for pY14Cav1 as an inhibitor of Src leading to Rho activation (Grande-Garcia et al., 2007) contrasts the critical role of Src kinase activity in phosphorylation of Cav1 and other FA components, such as FAK, leading to FA disassembly. As such, the formation of a stable pY14Cav1 containing domain within the FA, as proposed in Fig. 10, remains hypothetical and pY14Cav1-dependent regulation of FA domains may invoke the temporal and spatial recruitment of pY14Cav1 to FAs and mechanistic details that remain to be defined.

Bottom Line: Expression of the Mgat5/galectin lattice alone induces FAs and cell spreading.In human MDA-435 cancer cells, Cav1 expression, but not mutant Y14FCav1, stabilizes FAK exchange and stimulates de novo FA formation in protrusive cellular regions.Thus, transmembrane crosstalk between the galectin lattice and pY14Cav1 promotes FA turnover by stabilizing FAK within FAs defining previously unknown, interdependent roles for galectin-3 and pY14Cav1 in tumor cell migration.

View Article: PubMed Central - PubMed

Affiliation: Department of Cellular and Physiological Sciences, Life Sciences Institute, University of British Columbia, Vancouver, British Columbia, Canada.

ABSTRACT
Both tyrosine-phosphorylated caveolin-1 (pY14Cav1) and GlcNAc-transferase V (Mgat5) are linked with focal adhesions (FAs); however, their function in this context is unknown. Here, we show that galectin-3 binding to Mgat5-modified N-glycans functions together with pY14Cav1 to stabilize focal adhesion kinase (FAK) within FAs, and thereby promotes FA disassembly and turnover. Expression of the Mgat5/galectin lattice alone induces FAs and cell spreading. However, FAK stabilization in FAs also requires expression of pY14Cav1. In cells lacking the Mgat5/galectin lattice, pY14Cav1 is not sufficient to promote FAK stabilization, FA disassembly, and turnover. In human MDA-435 cancer cells, Cav1 expression, but not mutant Y14FCav1, stabilizes FAK exchange and stimulates de novo FA formation in protrusive cellular regions. Thus, transmembrane crosstalk between the galectin lattice and pY14Cav1 promotes FA turnover by stabilizing FAK within FAs defining previously unknown, interdependent roles for galectin-3 and pY14Cav1 in tumor cell migration.

Show MeSH
Related in: MedlinePlus