The world's first wiki where authorship really matters (Nature Genetics, 2008). Due credit and reputation for authors. Imagine a global collaborative knowledge base for original thoughts. Search thousands of articles and collaborate with scientists around the globe.

wikigene or wiki gene protein drug chemical gene disease author authorship tracking collaborative publishing evolutionary knowledge reputation system wiki2.0 global collaboration genes proteins drugs chemicals diseases compound
Hoffmann, R. A wiki for the life sciences where authorship matters. Nature Genetics (2008)



Gene Review

sqh  -  spaghetti squash

Drosophila melanogaster

Synonyms: CG3595, DmMRLC_C, Dmel\CG3595, MLC, MLRC, ...
Welcome! If you are familiar with the subject of this article, you can contribute to this open access knowledge base by deleting incorrect information, restructuring or completely rewriting any text. Read more.

Disease relevance of sqh


High impact information on sqh


Biological context of sqh

  • Germ line cystoblasts entirely lacking a functional sqh gene show severe defects in proliferation and cytokinesis [4].
  • Mutant sqh transgene sqh-A20, A21 in which both serine-21 and threonine-20 have been replaced by alanines behaves in most respects identically to the null allele in this system, with the exception that no heavy chain aggregates are found [4].
  • This suggests that sqh mutant phenotypes are chiefly caused by sequestration of myosin into inactive aggregates [5].
  • These findings suggest that increased levels of RLC phosphorylation do not contribute to disruption of the actomyosin hexagonal array [6].
  • Although immunolocalization can only suggest possible function, these myosin localizations and the coincident changes in cell morphology are consistent with a key role for non-muscle myosin in powering cellularization and gastrulation during embryogenesis [7].

Anatomical context of sqh

  • In addition, numerous aggregates of myosin heavy chain accumulate in the sqh null cells [4].
  • Although activated PAK does not disrupt the actomyosin cytoskeleton, it induces increased levels of Ser21 phosphorylated RLC [6].
  • At the syncytial blastoderm stage, myosin is found within cytoskeletal caps associated with the somatic nuclei at the embryonic surface [7].
  • During cellularization, myosin is concentrated around the furrow canals that form the leading margin of the plasma membrane as it plunges inward to package each somatic nucleus into a columnar epithelial cell [7].
  • In the preblastoderm embryo, myosin is localized to the egg cortex, sub-cortical arrays of inclusions, and, diffusely, the yolk-free periplasm [7].

Associations of sqh with chemical compounds

  • Here we show that the S. pombe myosin light chain Cdc4p is phosphorylated in vivo on either serine 2 or 6 but not both [8].

Enzymatic interactions of sqh

  • The I(20)/I(10) equatorial intensity ratio of the mutant fly is 35% less than that of wild type, supporting the hypothesis that myosin heads that lack phosphorylated RLC remain close to the thick filament backbone [9].

Regulatory relationships of sqh


Other interactions of sqh


Analytical, diagnostic and therapeutic context of sqh

  • Although these regulators act to promote stable myosin accumulation and apical cell constriction, loss-of-function phenotypes for each of these pathway members is not equivalent, suggesting the existence of additional ventral furrow regulators [12].


  1. Planar polarization of the denticle field in the Drosophila embryo: Roles for Myosin II (Zipper) and Fringe. Walters, J.W., Dilks, S.A., Dinardo, S. Dev. Biol. (2006) [Pubmed]
  2. The regulatory light chain of nonmuscle myosin is encoded by spaghetti-squash, a gene required for cytokinesis in Drosophila. Karess, R.E., Chang, X.J., Edwards, K.A., Kulkarni, S., Aguilera, I., Kiehart, D.P. Cell (1991) [Pubmed]
  3. Impairment of muscle function caused by mutations of phosphorylation sites in myosin regulatory light chain. Tohtong, R., Yamashita, H., Graham, M., Haeberle, J., Simcox, A., Maughan, D. Nature (1995) [Pubmed]
  4. Myosin light chain-activating phosphorylation sites are required for oogenesis in Drosophila. Jordan, P., Karess, R. J. Cell Biol. (1997) [Pubmed]
  5. Drosophila nonmuscle myosin II has multiple essential roles in imaginal disc and egg chamber morphogenesis. Edwards, K.A., Kiehart, D.P. Development (1996) [Pubmed]
  6. Role of myosin-II phosphorylation in V12Cdc42-mediated disruption of Drosophila cellularization. Crawford, J.M., Su, Z., Varlamova, O., Bresnick, A.R., Kiehart, D.P. Eur. J. Cell Biol. (2001) [Pubmed]
  7. Dynamic changes in the distribution of cytoplasmic myosin during Drosophila embryogenesis. Young, P.E., Pesacreta, T.C., Kiehart, D.P. Development (1991) [Pubmed]
  8. Phosphorylation of the myosin-II light chain does not regulate the timing of cytokinesis in fission yeast. McCollum, D., Feoktistova, A., Gould, K.L. J. Biol. Chem. (1999) [Pubmed]
  9. In vivo x-ray diffraction of indirect flight muscle from Drosophila melanogaster. Irving, T.C., Maughan, D.W. Biophys. J. (2000) [Pubmed]
  10. Rho Kinase's Role in Myosin Recruitment to the Equatorial Cortex of Mitotic Drosophila S2 Cells Is for Myosin Regulatory Light Chain Phosphorylation. Dean, S.O., Spudich, J.A. PLoS ONE (2006) [Pubmed]
  11. Myosin VIIA defects, which underlie the Usher 1B syndrome in humans, lead to deafness in Drosophila. Todi, S.V., Franke, J.D., Kiehart, D.P., Eberl, D.F. Curr. Biol. (2005) [Pubmed]
  12. Abelson kinase (Abl) and RhoGEF2 regulate actin organization during cell constriction in Drosophila. Fox, D.T., Peifer, M. Development (2007) [Pubmed]
WikiGenes - Universities