Phosphatase Subfamily Slingshot
Slingshot regulates cofilin phosphorylation with LIMK kinase subfamily.
Slingshot is found across holozoa, but absent from nematodes.
Slingshot has four domains defined experimentally: A domain (1-124), B domain (125-308), phosphatase domain (309-450) and Serine-enriched region close to the C-terminus (numbering from human SSH1) . The B domain includes the Pfam domain DEK_C. The A domain is required for the F-actin-mediated activation of SSH1 and therefore may mediate slingshot binding to actin. F-actin increased the cofilin-phosphatase activity of SSH1 more than 1200-fold. The B domain and phosphatase domain are indispensable for phosphorylated-cofilin (P-cofilin) binding. The phosphatase domain alone is sufficient for the phosphatase activity toward p-nitrophenyl phosphate (pNPP) . The motifs LHKACE (AA 185–190) in the B domain and LKRSHS (AA 973–978) in the S domain of SSH1 may also contribute to F-actin binding .
Slingshot dephosphorylates cofilin, a ubiquitous actin-binding factor required for the reorganization of actin filaments, in Drosophila and human  (see here for cofilin function). The three human slingshot genes are significantly different in subcellular distribution, actin-binding activity, phosphatase activity and expression patterns . Coronin 1B has also been proposed to be a slingshot substrate .
Slingshot is regulated by protein kinase D (PKD), which phosphorylates serines 937 and 978 and regulates human SSH1 subcellular localization by binding of 14-3-3 proteins . PKD also phosphorylates serine 402 to inhibit phosphatase activity . 14-3-3zeta/tau heterodimers regulate Slingshot activity in migrating keratinocytes . SSH1 is activated by its release from a regulatory complex with 14-3-3zeta protein through the redox-mediated oxidation of 14-3-3zeta .
- Kurita S, Watanabe Y, Gunji E, Ohashi K, and Mizuno K. Molecular dissection of the mechanisms of substrate recognition and F-actin-mediated activation of cofilin-phosphatase Slingshot-1. J Biol Chem. 2008 Nov 21;283(47):32542-52. DOI:10.1074/jbc.M804627200 |
- Yamamoto M, Nagata-Ohashi K, Ohta Y, Ohashi K, and Mizuno K. Identification of multiple actin-binding sites in cofilin-phosphatase Slingshot-1L. FEBS Lett. 2006 Mar 20;580(7):1789-94. DOI:10.1016/j.febslet.2006.02.034 |
- Niwa R, Nagata-Ohashi K, Takeichi M, Mizuno K, and Uemura T. Control of actin reorganization by Slingshot, a family of phosphatases that dephosphorylate ADF/cofilin. Cell. 2002 Jan 25;108(2):233-46. DOI:10.1016/s0092-8674(01)00638-9 |
- Ohta Y, Kousaka K, Nagata-Ohashi K, Ohashi K, Muramoto A, Shima Y, Niwa R, Uemura T, and Mizuno K. Differential activities, subcellular distribution and tissue expression patterns of three members of Slingshot family phosphatases that dephosphorylate cofilin. Genes Cells. 2003 Oct;8(10):811-24.
- Cai L, Marshall TW, Uetrecht AC, Schafer DA, and Bear JE. Coronin 1B coordinates Arp2/3 complex and cofilin activities at the leading edge. Cell. 2007 Mar 9;128(5):915-29. DOI:10.1016/j.cell.2007.01.031 |
- Peterburs P, Heering J, Link G, Pfizenmaier K, Olayioye MA, and Hausser A. Protein kinase D regulates cell migration by direct phosphorylation of the cofilin phosphatase slingshot 1 like. Cancer Res. 2009 Jul 15;69(14):5634-8. DOI:10.1158/0008-5472.CAN-09-0718 |
- Barišić S, Nagel AC, Franz-Wachtel M, Macek B, Preiss A, Link G, Maier D, and Hausser A. Phosphorylation of Ser 402 impedes phosphatase activity of slingshot 1. EMBO Rep. 2011 Jun;12(6):527-33. DOI:10.1038/embor.2011.53 |
- Kligys K, Yao J, Yu D, and Jones JC. 14-3-3zeta/tau heterodimers regulate Slingshot activity in migrating keratinocytes. Biochem Biophys Res Commun. 2009 Jun 12;383(4):450-4. DOI:10.1016/j.bbrc.2009.04.031 |
- Kim JS, Huang TY, and Bokoch GM. Reactive oxygen species regulate a slingshot-cofilin activation pathway. Mol Biol Cell. 2009 Jun;20(11):2650-60. DOI:10.1091/mbc.e09-02-0131 |