title: Structural features of LC8-induced self-association of swallow.
abstract: Cell functions depend on the collective activity of protein networks within which a few proteins, called hubs, participate in a large number of interactions. Dynein light chain LC8, first discovered as a subunit of the motor protein dynein, is considered to have a role broader than that of dynein, and its participation in diverse systems fits the description of a hub. Among its partners is Swallow with which LC8 is essential for proper localization of bicoid mRNA at the anterior cortex of Drosophila oocytes. Why LC8 is essential in this process is not clear, but emerging evidence suggests that LC8 functions by promoting self-association and/or structural organization of its diverse binding partners. This work addresses the energetics and structural features of LC8-induced Swallow self-association distant from LC8 binding. Mutational design based on a hypothetical helical wheel, intermonomer nuclear Overhauser effects assigned to residues expected at interface positions, and circular dichroism spectral characteristics indicate that the LC8-promoted dimer of Swallow is a coiled coil. Secondary chemical shifts and (15)N backbone relaxation identify the boundaries and distinguishing structural features of the coiled coil. Thermodynamic analysis of Swallow polypeptides designed to decouple self-association from LC8 binding reveals that the higher binding affinity of the engineered bivalent Swallow is of purely entropic origin and that the linker separating the coiled coil from the LC8 binding site remains disordered. We speculate that the LC8-promoted coiled coil is critical for bicoid mRNA localization because it favors structural organization of Swallow, which except for the central LC8-promoted coiled coil is primarily disordered.
authors.affiliation: Department of Biochemistry and Biophysics, Oregon State University , Corvallis, Oregon 97331, United States.
authors.forename: Ariam I
authors.initials: AI
authors.lastname: Kidane
authors.forename: Yujuan
authors.initials: Y
authors.lastname: Song
authors.forename: Afua
authors.initials: A
authors.lastname: Nyarko
authors.forename: Justin
authors.initials: J
authors.lastname: Hall
authors.forename: Michael
authors.initials: M
authors.lastname: Hare
authors.forename: Frank
authors.initials: F
authors.lastname: Löhr
authors.forename: Elisar
authors.initials: E
authors.lastname: Barbar
mesh_terms: D000818:Animals; D002151:Calorimetry; D002850:Chromatography, Gel; D002942:Circular Dichroism; D004330:Drosophila; D029721:Drosophila Proteins / Q000737:chemistry*; D004398:Dyneins / Q000737:chemistry*; D019906:Nuclear Magnetic Resonance, Biomolecular; D011485:Protein Binding; D011487:Protein Conformation; D016601:RNA-Binding Proteins / Q000737:chemistry*; D012542:Scattering, Radiation
chemical_list: D029721:Drosophila Proteins; D016601:RNA-Binding Proteins; C542608:ctp protein, Drosophila; C073970:swa protein, Drosophila; D004398:Dyneins
references.citation: J Mol Biol. 1996 Oct 25;263(2):344-58
references.pmid: 8913311
references.citation: Nat Commun. 2012 May 08;3:816
references.pmid: 22569364
references.citation: Nat Cell Biol. 2007 Jul;9(7):788-96
references.pmid: 17546040
references.citation: Essays Biochem. 2000;35:75-87
references.pmid: 12471891
references.citation: Adv Protein Chem. 1992;43:313-61
references.pmid: 1442323
references.citation: Development. 2010 Jan;137(1):169-76
references.pmid: 20023172
references.citation: Nat Cell Biol. 2000 Apr;2(4):185-90
references.pmid: 10783235
references.citation: Cell. 1988 Jul 1;54(1):83-93
references.pmid: 3383244
references.citation: J Biol Chem. 2013 Jan 25;288(4):2614-22
references.pmid: 23223634
references.citation: Genesis. 2004 Aug;39(4):280-7
references.pmid: 15287001
references.citation: J Biol Chem. 2012 Apr 6;287(15):11981-90
references.pmid: 22356912
references.citation: Dev Cell. 2002 Nov;3(5):685-96
references.pmid: 12431375
references.citation: J Magn Reson. 2010 Mar;203(1):190-8
references.pmid: 20031460
references.citation: J Mol Biol. 2008 Dec 26;384(4):954-66
references.pmid: 18948118
references.citation: Biochemistry. 2008 Jan 15;47(2):503-8
references.pmid: 18092820
references.citation: EMBO J. 1988 Jun;7(6):1749-56
references.pmid: 2901954
references.citation: Science. 1991 May 24;252(5009):1162-4
references.pmid: 2031185
references.citation: Proc Natl Acad Sci U S A. 2007 Jun 12;104(24):10028-33
references.pmid: 17551010
references.citation: J Mol Biol. 2006 Oct 6;362(5):1082-93
references.pmid: 16949604
references.citation: Proteins. 1995 Sep;23(1):83-96
references.pmid: 8539253
references.citation: Proc Natl Acad Sci U S A. 1981 Jul;78(7):4046-50
references.pmid: 16593049
references.citation: J Mol Biol. 1999 Sep 17;292(2):195-202
references.pmid: 10493868
references.citation: J Cell Biol. 2010 Oct 18;191(2):269-80
references.pmid: 20937697
references.citation: Science. 1994 Feb 11;263(5148):777-84
references.pmid: 8303294
references.citation: Dev Genes Evol. 2002 Jun;212(5):239-47
references.pmid: 12070614
references.citation: Methods Mol Biol. 2004;278:313-52
references.pmid: 15318002
references.citation: Biochemistry. 2002 Apr 2;41(13):4302-11
references.pmid: 11914076
references.citation: Protein Sci. 2006 Dec;15(12):2795-804
references.pmid: 17088319
references.citation: J Biol Chem. 2005 Mar 4;280(9):8172-9
references.pmid: 15611139
references.citation: Nat Cell Biol. 2000 Apr;2(4):E60-2
references.pmid: 10783251
references.citation: Biochemistry. 2004 Apr 20;43(15):4611-20
references.pmid: 15078108
references.citation: J Biol Chem. 2011 Jan 14;286(2):1556-66
references.pmid: 20974845
references.citation: Biochem Biophys Res Commun. 2008 Oct 31;375(4):634-8
references.pmid: 18725194
references.citation: J Biol Chem. 2006 Jul 14;281(28):19092-9
references.pmid: 16684779
references.citation: J Mol Biol. 2007 Aug 10;371(2):457-68
references.pmid: 17570393
references.citation: J Biol Chem. 2009 Nov 27;284(48):33115-21
references.pmid: 19759397
references.citation: J Biol Chem. 2007 Jun 8;282(23):17272-9
references.pmid: 17428790
references.citation: Mol Biol Cell. 2012 Oct;23(19):3911-22
references.pmid: 22875988
references.citation: Cancer Cell. 2004 Jun;5(6):575-85
references.pmid: 15193260
references.citation: Dev Genes Evol. 2000 Sep;210(8-9):426-35
references.pmid: 11180848