Images in the banner (from left to right and top to bottom): DLG-1/Discs large::GFP during dorsal intercalation [M. Köppen]; Pdlg-1::GFP during ventral enclosure [M. Sheffield]; AJM-1 (green) and muscle (red) during elongation [P. Heid]; HMP-2/beta-catenin electrostatic surface [H.-J. Choi]; AJM-1 (green) and muscle (red) in an elongated embryo [A. Cox-Paulson]; phalloidin staining in elongated embryo [M. Costa]
Jeff Hardin • Department of Integrative Biology, University of Wisconsin • 327 Zoology Research Building • 1117 W. Johnson St. • Madison, WI 53706
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Recent NewsNovember 2017
SRGP-1/srGAP stabilizes adherens junctions in the C. elegans embryo (in preparation).
HMP-1ΔVH2::GFP (green) and SRGP-1::mCherry (magenta) fail to colocalize in a comma stage embryo ( Bethany Lucas and Xiangqiang Shao).
srGAP review: Lucas, B. and Hardin, J. (2017). Mind the (sr)GAP – roles of Slit-Robo GAPs in neurons, brains and beyond. J. Cell Sci., in press. PubMed
SORB-1/Sorbin plays roles in sarcomere organization in C. elegans. Loveless, T., Qadota, H., Benian, GM., and Hardin, J. (2017). C. elegans SORB-1 localizes to integrin adhesion sites and is required for organization of sarcomeres and mitochondria in myocytes. Mol. Bio. Cell, in press. PubMed
SORB-1::GFP (green) translocates to the nucleus in pat-2//α-integrin(RNAi) embryos. DAPI counterstains nuclei (magenta; Tim Loveless).
Fine-mapping α-/β-catenin binding interface in vitro and in vivo (with Hee-Jung Choi's group). Shao, X. Kang, H., Loveless, T., Lee, G.R., , Seok, C., Weis, W.I., and Choi, H.-J., and Hardin, J. (2017). Cell–cell adhesion in metazoans relies on evolutionarily conserved features of the α-catenin•β-catenin–binding interface. J. Biol. Chem. 292,16477–16490. PubMed
Surface rendering of HMP-1/α-catenin (green) and HMP-2/β-catenin (aqua). Rendering by Tim Loveless
Student news: Congratulations to new Genetics PhDs Drs. Bethany Lucas and Xiangqiang Shao, who both defended their theses.
The structure of a C. elegans α-catenin. Kang et al (2017). Structural and functional characterization of Caenorhabditis elegans α-catenin reveals constitutive binding to β-catenin and actin. (with Hee-Jung Choi's group; J. Biol. Chem. 29, 7077-7086). PubMed
The N terminus (purple, yellow), M domain (green, aqua) and a homology model of the actin-binding domain (red) of HMP-1/α-catenin fitted into the SAXS envelope of HMP-1. Rendering by Hee-Jung Choi.
Walck-Shannon et al. (2016). CDC-42 orients cell migration during epithelial intercalation in the Caenorhabditis elegans epidermis. PLOS Genetics 12(11): e1006415 PubMed
Confocal images of an epidermal cytoplasmic reporter (Plbp-1::GFP) in wild-type (WT) (left) and ZF1::cdc-42; cdc-42(gk388) (right) embryos, in which there is late maternal loss of CDC-42, 45 min. after terminal division. Scale bar is 5 μm. [Elise Walck-Shannon]
F1000 review of the cadherin/catenin complex in C. elegans. F1000Research 2015, 4(F1000 Faculty Rev):1473 (doi: 10.12688/f1000research.6866.1) PubMed
Older NewsOctober 2015
Proteomic analysis of the cadherin/catenin complex in C. elegans (collaboration with Jon Audhys's group):
Callaci, S., Morrison, K., Shao, X., Schuh, A.L. Wang, Y., Yates III, J.R., Hardin, J., and Audhya, A. (2015). Phosphoregulation of the C. elegans cadherin-catenin complex. Biochemistry 472:339-52.. PubMed
hmp-1 mutant embryo rescued with a quadruple mutant phosphomimetic form of HMP-1 tagged with gfp (Xiangqiang Shao).
Dorsal intercalation in C. elegans uses a conserved Trio/CARMIL system upstream of Rac and RhoG. Development 142, 3549-3560. PubMed
crml-1(gm326) dorsal cells have excessive protrusive activity, which can be suppressed by GEF1 loss of function n unc-73(rh40) mutants. Left-hand cells are psuedocolored green. Yellow arrows denote excessive, lateral protrusions. Scale bar is 5 μm. [Elise Walck-Shannon]
Student news: Congratulations to Elise Walck-Shannon, who defended her thesis July 29, 2015!
Blake Martin received a Gilliam fellowship from HHMI!
Angstroms to embryos: structure-function analysis of the cadherin complex in C. elegans
(collaboration with Bill Weis, Stanford, and Hee-Jung Choi, Seoul Nat. Univ.; Developmental Cell 33, 82–93)
Electrostatic representation of zebrafish β-catenin (left) and C. elegans HMP-2 (right). [Hee-Jung Choi, Bill Weis, Tim Loveless]
Minor updates to ImageJ plugins
are available. Go to the Microscopy page.
Cell rearrangement review
Walck-Shannon, E. and Hardin, J. (2014). Cell intercalation from top to bottom. Nature Rev. Mol. Cell. Bio 15:34-48. Pubmed
Mapping functionally important domains in the C terminus of α-catenin
Maiden, S.L., Harrison, N., Keegan, J., Cain, B., Lynch, A.M., Pettitt, J., and Hardin, J. Specific conserved C-terminal amino acids of Caenorhabditis elegans HMP-1/α-catenin modulate F-actin binding independently of vinculin. J. Biol. Chem. 288:5694-706. PubMed
Homology model of the C terminus o HMP-1/α-catenin, using the metavinculin VH3 domain crystal structure as a template. Residues mutated in hmp-1 alleles are shown as space-filled molecules labeled with the amino acid number. (A) and (B) Residues mutated in strong loss-of-function alleles. (C) Residues mutated in hmp-1(fe4) and intragenic suppressor alleles. [Stephanie Maiden]
MAGI-1, AFD-1/afadin, and the cadherin interactome during morphogenesis
Lynch, A.M., Grana, T., Cox-Paulson, E., Couthier, A., Cameron, M., Chin-Sang, I., Pettitt, J., and Hardin, J. (2012). A genome-wide functional screen identifies MAGI-1 as an L1CAM-dependent stabilizer of apical junctions in C. elegans. Curr. Biol 22, 1891–1899. PubMed
Top: Wild-type embryo expressing an actin reporter during ventral enclosure. Bottom: a magi-1(RNAi) embryo. Cells migrate ventrally, but migration is irregular and cells display excess protrusive activity at the ventral midline. [Allison Lynch]
Tropomodulin protects adherens junctions under stress during morphogenesis
Cox-Paulson, E., Walck-Shannon, E., Lynch, A., Yamashiro, S., Zaidel-Bar, R., Celeste C. Eno, C., Ono, S., and Hardin, J. (2012). Tropomodulin protects α-catenin-dependent junctional actin networks under stress during epithelial morphogenesis. Curr. Biol. 22:1500-1505. PubMed
hmp-1/α-catenin and unc-94/tropomodulin synergistically regulate embryonic morphogenesis. Purple, F-actin (phalloidin staining); green, JAC-1/p120ctn::GFP. Left: a hmp-1(fe4) embryo at the 1.5-fold stage. Junctions are largely normal. Right: a hmp-1(fe4);unc-94(RNAi) embryo. Junctions between seam cells and ventral and dorsal epidermal cells have ripped apart [Abbi Cox-Paulson]
Cell migration during ventral enclosure
Ikegami, R., Simokat, K., Zheng, H., Dixon, L., Garriga, G., Hardin, J. and Culotti, J. (2012). Semaphorin and Eph receptor signaling guide a series of cell movements for ventral enclosure in C. elegans. Curr. Biol. 22:1–11. PubMed
Ventral view of the pocket region of an embryo expressing Pplx-2::gfp; anterior at top right. The ventral midline (dashed line) and relative positions of expressing identified P cells (circles, closed circles are P9/10) and plexin expressing cells on the surface of the open ventral pocket (colored squares) are indicated. [Kristin Simokat and Richard Ikegami]
Maiden, S.L. and Hardin, J. (2011). The secret life of α-catenin: moonlighting during morphogenesis. J. Cell Biol. 195:543–552. PubMed
Loss of the RhoGAP SRGP-1 promotes the clearance of dead and injured cells
Neukomm, L.J., Frei, A.P., Cabello, J., Kinchen, J.M., Zaidel-Bar, R., Ma, Z., Haney, L.B., Hardin, J., Ravichandran, K.S., Moreno, S., and Hengartner, M.O. (2011). Loss of the RhoGAP SRGP1 promotes the clearance of dead and injured cells in Caenorhabditis elegans. Nature Cell Biol. 13:79-86. PubMed
ced-6 larvae accumulate cell corpses due to engulfment defects (arrowheads, left). Engulfment defects are suppressed in ced-6;srgp-1 double mutants (right). [Lukas Neukomm]
SRGP-1/srGAP regulates membrane protrusion during cell-cell adhesion
(Zaidel-Bar, R., Joyce, M.J., Lynch, A.M., Witte, K., Audhya, A., and Hardin, J. (2010). The F-BAR domain of SRGP-1 facilitates cell-cell adhesion during C. elegans morphogenesis. J. Cell Biol. 191, 761-9.) PubMed JCB In This Issue
November 15, 2010 cover!
Embryo expressing SRGP-1::GFP (green) stained for actin (purple).
The inset shows extensive induced tubulations. [Ronen Zaidel-Bar].
Intramolecular regulation of alpha-catenin's ability to bind actin
(Kwiatkowski, A.V., Maiden, S.L., Pokutta, S., Choi, H.-J., Benjamin, J.M., Lynch, A.M., Nelson, W.J., Weis, W.I., and Hardin, J. (2010). In vitro and in vivo reconstitution of the cadherin-catenin-actin complex from Caenorhabditis elegans. PNAS 107,14591-14596.)
August 17, 2010 cover!
Color adjusted image of a hmp-1(zu278) mutant
embryo stained with phalloidin. [Stephanie Maiden].
Cadherins and L1CAMs during cell-cell adhesion and gastrulation
(Grana, T.M., Cox, E.A., Lynch, A.M., and Hardin, J. (2010). SAX-7/L1CAM and HMR-1/cadherin function redundantly in blastomere compaction and non-muscle myosin accumulation. Dev. Biol. 344, 731–744.)
Color adjusted image of a devitellinized hmr-1(RNAi);sax-7(eq1) C. elegans embryo. Blastomeres are loosely adherent and cell division orientations are abnormal. [Theresa Grana].
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