Journal: eLife
Article Title: Cas phosphorylation regulates focal adhesion assembly
doi: 10.7554/eLife.90234
Figure Lengend Snippet: ( A ) Rac1 requires Cas to induce cell spreading. Images and quantification of MCF10A cells expressing EGFP-Rac1WT or -Rac1Q61L that were treated with control or Cas siRNA and fixed after 30 min of spreading. ( B, C ) Reactive oxygen species (ROS) regulates Rac1 activation, Rac1 activation, cell spreading and vinculin recruitment to Cas clusters. ( B ) FRET images and quantification of Rac1-2G MCF10A cells treated with DMSO or NADPH-dependent oxidase inhibitor diphenylamineiodonium (DPI) and fixed after 30 min of spreading. ( C ) Images and quantification of Cas mSc YFP-VCL MCF10A cells treated with DMSO or DPI. Graphs show mean cell area, mean Cas mSc and YFP-VCL intensity, and median Δ t 1/2 (VCL-Cas) from 7 to 12 cells in three biological repeats. ( D ) Inhibiting Cullins accelerates vinculin recruitment to Cas clusters. Images and quantification of Cas mSc YFP-VCL MCF10A cells treated with control or SOCS6 siRNA or with DMSO or Cullin Neddylation inhibitor MLN4924. Graphs show median Δ t 1/2 (VCL-Cas) from 8 to 12 cells in three biological repeats. All error bars represent mean and standard error of the mean (SEM) and all p values by Mann–Whitney U -tests. ( E ) Two-step model. In the first step, co-clustering of Cas with inactive integrin leads to SFK-dependent phosphorylation of Cas, recruitment of Crk/CrkL, activation of Rac1, ROS production, and positive feedback that strengthens and maintains signaling to form a nascent adhesion. Positive feedback is opposed by negative feedback resulting from CRL5 SOCS6 . In a second step, integrin β1 is activated and talin1, kindlin2, vinculin, actin, and other proteins are recruited to form a focal adhesion. The second step may be triggered by growth of the nascent adhesion to a critical size, or by decreased occupancy with Cas. See Discussion for details.
Article Snippet: Following antibodies were used: mouse anti-Cas (610271) (BD Biosciences); rabbit-phospho-Y410Cas (4011S) and phospho-Y249Cas (4014S) (Cell Signaling Technology); mouse anti-vinculin (V9131, Sigma-Aldrich); mouse anti-Crk (610035) (BD Transduction labs); mouse anti-CrkL (05-414) (Upstate); sheep anti-paxillin (AF4259, R and D Systems); rabbit anti-pY31 paxillin (44-720G, Biosource); rat anti-integrin-β1 (9EG7, 553715) and mouse anti-paxillin (610051) (BD Biosciences); rabbit anti-Talin1 (A14168-1-AP), rabbit-anti Kindlin2 (11453-1-AP), and mouse anti-FAK (66258-1-Ig) (Proteintech); rat anti-integrin-β1 (mAB13, MABT821), rabbit anti-integrin β1 (AB1952P), mouse anti-integrin β1 (12G10, MAB2247) (Millipore); rabbit-anti-integrin-β3 (A2542), rabbit-anti-integrin-αv (A2091) (abclonal); rat anti-integrin-β1 (AIIB2), mouse anti-integrin α5β1 (P8D4), and mouse anti-integrin α2β1 (P1E6) (Developmental Studies Hybridoma Bank); AlexaFluor 488 goat anti-rabbit IgG (H+L), AlexaFluor 488 goat anti-mouse IgG (H+L), AlexaFluor 647 goat anti-mouse IgG (H+L), AlexaFluor 647 goat anti-sheep IgG (H+L), and AlexaFluor 633 goat anti-rat IgG (H+L) (Invitrogen); IRDye 680RD goat anti-mouse and IRDye 800CW goat anti-rabbit (LI-COR).
Techniques: Expressing, Activation Assay, MANN-WHITNEY