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LKB1 kinase-dependent and -independent defects disrupt polarity and adhesion signaling to drive collagen remodeling during invasion.

Konen J, Wilkinson S, Lee B, Fu H, Zhou W, Jiang Y, Marcus AI - Mol. Biol. Cell (2016)

Bottom Line: The majority of LKB1 mutations are truncations that disrupt its kinase activity and remove its C-terminal domain (CTD).Instead, cell polarity is overseen by the kinase-independent function of its CTD and more specifically its farnesylation.This occurs through a mesenchymal-amoeboid morphological switch that signals through the Rho-GTPase RhoA.

View Article: PubMed Central - PubMed

Affiliation: Department of Hematology and Medical Oncology, Winship Cancer Institute of Emory University, Atlanta, GA 30322 Graduate Program in Cancer Biology, Emory University, Atlanta, GA 30322.

No MeSH data available.


Related in: MedlinePlus

Kinase activity of LKB1 represses collagen remodeling. (A) Multiphoton imaging was performed at 0 and 24 h to visualize collagen using H157 stables with the following LKB1 constructs: empty GFP control, LKB1 WT, LKB1 C430S (farnesylation mutant), LKB1 K78I (kinase dead), and LKB1 K78I-C430S. (B) Images obtained in A were quantified for collagen alignment using CT-FIRE image analysis. (C) Collagen SHG imaging of MARK1 siRNA–depleted H157 LKB1 wild-type stable cells compared with scrambled siRNA. (D) Zoomed images showing collagen and single invading cells. Arrow, amoeboid cell that remodels collagen; arrowhead, amoeboid cell that does not remodel collagen. Scale, 50 μm.
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Figure 8: Kinase activity of LKB1 represses collagen remodeling. (A) Multiphoton imaging was performed at 0 and 24 h to visualize collagen using H157 stables with the following LKB1 constructs: empty GFP control, LKB1 WT, LKB1 C430S (farnesylation mutant), LKB1 K78I (kinase dead), and LKB1 K78I-C430S. (B) Images obtained in A were quantified for collagen alignment using CT-FIRE image analysis. (C) Collagen SHG imaging of MARK1 siRNA–depleted H157 LKB1 wild-type stable cells compared with scrambled siRNA. (D) Zoomed images showing collagen and single invading cells. Arrow, amoeboid cell that remodels collagen; arrowhead, amoeboid cell that does not remodel collagen. Scale, 50 μm.

Mentions: We next wanted to test the hypothesis that LKB1 kinase activity represses collagen remodeling. Therefore we assessed collagen remodeling and invasion in H157 cells stably expressing various LKB1 domains or mutants. At 24 h, H157 empty GFP–invading cells show epicenters of significant collagen alignment (Figure 8Ai), whereas cells expressing either LKB1 wild type or LKB1 C430S show significantly less alignment (Figure 8A, ii and iii). However, cells expressing either the K78I kinase-dead LKB1 or the K78I-C430S double mutant LKB1 fail to repress alignment (Figure 8A, iv and v), suggesting that kinase activity is required for collagen remodeling. Quantification of alignment shows that empty GFP, LKB1 K78I, and LKB1 K78I-C430S cells have increased alignment coefficients compared with those cells expressing LKB1 wild type or C430S (Figure 8B).


LKB1 kinase-dependent and -independent defects disrupt polarity and adhesion signaling to drive collagen remodeling during invasion.

Konen J, Wilkinson S, Lee B, Fu H, Zhou W, Jiang Y, Marcus AI - Mol. Biol. Cell (2016)

Kinase activity of LKB1 represses collagen remodeling. (A) Multiphoton imaging was performed at 0 and 24 h to visualize collagen using H157 stables with the following LKB1 constructs: empty GFP control, LKB1 WT, LKB1 C430S (farnesylation mutant), LKB1 K78I (kinase dead), and LKB1 K78I-C430S. (B) Images obtained in A were quantified for collagen alignment using CT-FIRE image analysis. (C) Collagen SHG imaging of MARK1 siRNA–depleted H157 LKB1 wild-type stable cells compared with scrambled siRNA. (D) Zoomed images showing collagen and single invading cells. Arrow, amoeboid cell that remodels collagen; arrowhead, amoeboid cell that does not remodel collagen. Scale, 50 μm.
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Related In: Results  -  Collection

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Figure 8: Kinase activity of LKB1 represses collagen remodeling. (A) Multiphoton imaging was performed at 0 and 24 h to visualize collagen using H157 stables with the following LKB1 constructs: empty GFP control, LKB1 WT, LKB1 C430S (farnesylation mutant), LKB1 K78I (kinase dead), and LKB1 K78I-C430S. (B) Images obtained in A were quantified for collagen alignment using CT-FIRE image analysis. (C) Collagen SHG imaging of MARK1 siRNA–depleted H157 LKB1 wild-type stable cells compared with scrambled siRNA. (D) Zoomed images showing collagen and single invading cells. Arrow, amoeboid cell that remodels collagen; arrowhead, amoeboid cell that does not remodel collagen. Scale, 50 μm.
Mentions: We next wanted to test the hypothesis that LKB1 kinase activity represses collagen remodeling. Therefore we assessed collagen remodeling and invasion in H157 cells stably expressing various LKB1 domains or mutants. At 24 h, H157 empty GFP–invading cells show epicenters of significant collagen alignment (Figure 8Ai), whereas cells expressing either LKB1 wild type or LKB1 C430S show significantly less alignment (Figure 8A, ii and iii). However, cells expressing either the K78I kinase-dead LKB1 or the K78I-C430S double mutant LKB1 fail to repress alignment (Figure 8A, iv and v), suggesting that kinase activity is required for collagen remodeling. Quantification of alignment shows that empty GFP, LKB1 K78I, and LKB1 K78I-C430S cells have increased alignment coefficients compared with those cells expressing LKB1 wild type or C430S (Figure 8B).

Bottom Line: The majority of LKB1 mutations are truncations that disrupt its kinase activity and remove its C-terminal domain (CTD).Instead, cell polarity is overseen by the kinase-independent function of its CTD and more specifically its farnesylation.This occurs through a mesenchymal-amoeboid morphological switch that signals through the Rho-GTPase RhoA.

View Article: PubMed Central - PubMed

Affiliation: Department of Hematology and Medical Oncology, Winship Cancer Institute of Emory University, Atlanta, GA 30322 Graduate Program in Cancer Biology, Emory University, Atlanta, GA 30322.

No MeSH data available.


Related in: MedlinePlus