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Tks5 recruits AFAP-110, p190RhoGAP, and cortactin for podosome formation

Luca Crimaldi1, Sara A Courtneidge, Mario Gimona

  • 1Department of Cell Biology and Oncology, Consorzio Mario Negri Sud, Via Nazionale, Santa Maria, Imbaro, Chieti, Italy. crimaldi@negrisud.it

Experimental Cell Research
|June 23, 2009
PubMed

Insights

The scaffold protein Tks5 is crucial for podosome formation in smooth muscle cells. It recruits key proteins like AFAP-110, p190RhoGAP, and cortactin, essential for cell structure and function.

Area of Science:

  • Cell Biology
  • Molecular Biology
  • Biochemistry

Background:

  • Podosome formation in vascular smooth muscle cells involves AFAP-110, p190RhoGAP, and cortactin.
  • The precise mechanism for recruiting these proteins to podosomes is not fully understood.
  • The scaffold protein Tks5 is localized to podosomes and may act as a specific adapter.

Purpose of the Study:

  • To elucidate the molecular mechanism of Tks5 in recruiting AFAP-110, p190RhoGAP, and cortactin during podosome formation.
  • To investigate the role of specific Tks5 domains in protein recruitment and podosome assembly.

Main Methods:

  • Tks5 mislocalization experiments to mitochondria.
  • Analysis of Tks5 deletion mutants (SH3 and PX domains).
  • Expression of catalytically inactive p190RhoGAP mutant and siRNA-mediated knock-down of p190RhoGAP.

Main Results:

  • Mislocalizing Tks5 to mitochondria inhibited podosome formation and redistributed AFAP-110, p190RhoGAP, and cortactin.
  • The fifth SH3 domain of Tks5 is essential for recruiting these proteins.
  • A Tks5 mutant lacking the PX domain also inhibited podosome formation and altered protein localization.
  • p190RhoGAP is necessary for podosome formation.

Conclusions:

  • Tks5 plays a central role in recruiting AFAP-110, p190RhoGAP, and cortactin for podosome formation.
  • Specific domains of Tks5, particularly the SH3 domain, are critical for this recruitment process.
  • Tks5 acts as a key scaffold protein orchestrating podosome assembly in smooth muscle cells.

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