Actin binding by Hip1 (huntingtin-interacting protein 1) and Hip1R (Hip1-related protein) is regulated by clathrin light chain.
The huntingtin-interacting protein family members (Hip1 and Hip1R in mammals and Sla2p in yeast) link clathrin-mediated membrane traffic to actin cytoskeleton dynamics. Genetic data in yeast have implicated the light chain subunit of clathrin in regulating this link. To test this hypothesis, the biophysical properties of mammalian Hip1 and Hip1R and their interaction with clathrin light chain and actin were analyzed. The coiled-coil domains (clathrin light chain-binding) of Hip1 and Hip1R were found to be stable homodimers with no propensity to heterodimerize in vitro. Homodimers were also predominant in vivo, accounting for cellular segregation of Hip1 and Hip1R functions. Coiled-coil domains of Hip1 and Hip1R differed in their stability and flexibility, correlating with slightly different affinities for clathrin light chain and more markedly with effects of clathrin light chain binding on Hip protein-actin interactions. Clathrin light chain binding induced a compact conformation of both Hip1 and Hip1R and significantly reduced actin binding by their THATCH domains. Thus, clathrin is a negative regulator of Hip-actin interactions. These observations necessarily change models proposed for Hip protein function.
Wilbur
Jeremy D
JD
Graduate Program in Biophysics, University of California, San Francisco, California 94143-0552, USA.
Chen
Chih-Ying
CY
Manalo
Venus
V
Hwang
Peter K
PK
Fletterick
Robert J
RJ
Brodsky
Frances M
FM
D000199:Actins / Q000737:chemistry*; D048868:Adaptor Proteins, Signal Transducing; D000818:Animals; D002966:Clathrin / Q000737:chemistry; D003599:Cytoskeleton / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000737:chemistry* / Q000378:metabolism; D019281:Dimerization; D004926:Escherichia coli / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D051379:Mice; D008840:Microfilament Proteins; D008954:Models, Biological; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D020349:Surface Plasmon Resonance; D033921:Vesicular Transport Proteins / Q000737:chemistry* / Q000378:metabolism
D000199:Actins; D048868:Adaptor Proteins, Signal Transducing; D002966:Clathrin; D004268:DNA-Binding Proteins; C073368:HIP1 protein, human; C489537:HIP1R protein, human; D008840:Microfilament Proteins; D033921:Vesicular Transport Proteins
Science. 1991 May 24;252(5009):1162-4
2031185
Nat Cell Biol. 2002 Feb;4(2):95-105
11788820
J Biol Chem. 2005 Feb 18;280(7):6109-17
15533940
J Cell Biol. 2005 Jul 18;170(2):191-200
16027218
Hum Mol Genet. 2007 Jun 1;16(11):1279-92
17452370
Biochemistry. 2003 Dec 9;42(48):14114-21
14640678
Annu Rev Cell Dev Biol. 2001;17:517-68
11687498
Mol Biol Cell. 2006 Oct;17(10):4343-52
16870700
J Mol Biol. 2007 Mar 16;367(1):8-15
17257618
Annu Rev Biochem. 2000;69:699-727
10966473
Mol Biol Cell. 1999 Jul;10(7):2265-83
10397764
Cell. 1999 Apr 16;97(2):165-74
10219238
Biochemistry. 2004 Dec 14;43(49):15418-28
15581353
J Cell Biol. 1985 Dec;101(6):2047-54
2415533
J Biol Chem. 2000 Dec 29;275(52):41299-308
11007801
J Mol Biol. 2008 Feb 1;375(5):1197-205
18155047
Annu Rev Cell Dev Biol. 2003;19:287-332
14570572
Structure. 2006 Jan;14(1):43-50
16407064
Mol Biol Cell. 2004 Apr;15(4):1666-79
14742709
Curr Opin Cell Biol. 2007 Aug;19(4):417-25
17631994
Mol Biol Cell. 1993 Jun;4(6):647-60
8374173
J Biol Chem. 2002 May 31;277(22):19897-904
11889126
J Cell Biol. 1999 Dec 27;147(7):1503-18
10613908
J Biol Chem. 2005 Feb 18;280(7):6101-8
15533941
J Biol Chem. 2004 Apr 16;279(16):16657-61
14985334
EMBO J. 2003 Jul 1;22(13):3254-66
12839988
Cell. 1995 Oct 20;83(2):257-67
7585943
EMBO J. 2007 Mar 7;26(5):1199-210
17318189
Trends Cell Biol. 2001 Feb;11(2):82-8
11166216
Proteins. 1996 Oct;26(2):134-45
8916221
J Cell Biol. 2001 Sep 17;154(6):1209-23
11564758
Biochim Biophys Acta. 2005 Jul 10;1744(3):415-37
15922462
Nat Struct Mol Biol. 2006 Feb;13(2):121-30
16415883
Nat Genet. 1997 May;16(1):44-53
9140394
Hum Mol Genet. 1997 Mar;6(3):487-95
9147654