Arabidopsis VILLIN5, an actin filament bundling and severing protein, is necessary for normal pollen tube growth.
A dynamic actin cytoskeleton is essential for pollen germination and tube growth. However, the molecular mechanisms underlying the organization and turnover of the actin cytoskeleton in pollen remain poorly understood. Villin plays a key role in the formation of higher-order structures from actin filaments and in the regulation of actin dynamics in eukaryotic cells. It belongs to the villin/gelsolin/fragmin superfamily of actin binding proteins and is composed of six gelsolin-homology domains at its core and a villin headpiece domain at its C terminus. Recently, several villin family members from plants have been shown to sever, cap, and bundle actin filaments in vitro. Here, we characterized a villin isovariant, Arabidopsis thaliana VILLIN5 (VLN5), that is highly and preferentially expressed in pollen. VLN5 loss-of-function retarded pollen tube growth and sensitized actin filaments in pollen grains and tubes to latrunculin B. In vitro biochemical analyses revealed that VLN5 is a typical member of the villin family and retains a full suite of activities, including barbed-end capping, filament bundling, and calcium-dependent severing. The severing activity was confirmed with time-lapse evanescent wave microscopy of individual actin filaments in vitro. We propose that VLN5 is a major regulator of actin filament stability and turnover that functions in concert with oscillatory calcium gradients in pollen and therefore plays an integral role in pollen germination and tube growth.
Zhang
Hua
H
Center for Signal Transduction and Metabolomics, Key Laboratory of Photosynthesis and Environmental Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China.
Qu
Xiaolu
X
Bao
Chanchan
C
Khurana
Parul
P
Wang
Qiannan
Q
Xie
Yurong
Y
Zheng
Yiyan
Y
Chen
Naizhi
N
Blanchoin
Laurent
L
Staiger
Christopher J
CJ
Huang
Shanjin
S
D000199:Actins / Q000378:metabolism*; D017360:Arabidopsis / Q000254:growth & development / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D019086:Bridged Bicyclo Compounds, Heterocyclic / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism; D015638:Cytochalasin D / Q000494:pharmacology; D008840:Microfilament Proteins / Q000235:genetics / Q000378:metabolism*; D009154:Mutation; D053205:Pollen Tube / Q000254:growth & development*; D018749:RNA, Plant / Q000235:genetics; D053778:Thiazolidines / Q000494:pharmacology
D000199:Actins; D029681:Arabidopsis Proteins; D019086:Bridged Bicyclo Compounds, Heterocyclic; D008840:Microfilament Proteins; D018749:RNA, Plant; D053778:Thiazolidines; C026615:villin; D015638:Cytochalasin D; C037068:latrunculin B; D002118:Calcium
Plant Cell. 1997 Aug;9(8):1445-1457
12237391
J Mol Biol. 1994 Aug 19;241(3):480-2
8064860
Plant Cell Physiol. 2003 Oct;44(10):1088-99
14581634
Plant Cell. 2005 Feb;17(2):486-501
15659626
Proc Natl Acad Sci U S A. 2001 Dec 18;98(26):15009-13
11742068
J Biol Chem. 2003 Nov 7;278(45):44832-42
12947123
J Biol Chem. 2000 Nov 10;275(45):35457-70
10956642
Plant J. 2000 Dec;24(5):625-36
11123801
Plant Cell. 2005 Aug;17(8):2296-313
15994911
Curr Opin Plant Biol. 2008 Dec;11(6):662-71
18977167
J Biol Chem. 1971 Aug 10;246(15):4866-71
4254541
Plant Physiol. 2008 Apr;146(4):1611-21
18263780
Plant Physiol. 2003 Jun;132(2):640-52
12805594
Nature. 2000 Apr 27;404(6781):1007-11
10801131
Plant Cell. 2006 Sep;18(9):2194-206
16905656
Mol Biol Cell. 2006 Apr;17(4):1946-58
16436516
Annu Rev Plant Biol. 2008;59:547-72
18444907
Curr Biol. 2006 Oct 10;16(19):1924-30
17027489
Plant Physiol. 2008 Aug;147(4):1619-36
18480376
Curr Opin Plant Biol. 2006 Dec;9(6):579-88
17010659
Plant Cell. 2009 Dec;21(12):3868-84
20023198
FEBS Lett. 2008 Jun 18;582(14):2128-39
18307996
Plant Cell. 2002 Sep;14(9):2175-90
12215514
Dev Biol. 2000 Jun 1;222(1):84-98
10885748
Plant Physiol. 2005 Jun;138(2):744-56
15908605
J Biol Chem. 2004 May 28;279(22):23364-75
15039433
Mol Biol Cell. 2001 Aug;12(8):2534-45
11514633
Plant J. 1997 Oct;12(4):957-63
9375406
Plant Cell. 2007 Jun;19(6):1930-46
17586658
Cell Motil Cytoskeleton. 1997;36(4):323-38
9096955
J Cell Biol. 2009 Jan 26;184(2):269-80
19171759
Biochemistry. 1984 Dec 4;23(25):6099-102
6525347
Plant Cell Physiol. 2005 Oct;46(10):1690-703
16100394
J Cell Biol. 1999 Aug 23;146(4):819-30
10459016
J Cell Biol. 1984 Sep;99(3):769-77
6540783
Cell. 1981 May;24(2):471-80
6894565
Cell. 1989 Nov 3;59(3):461-75
2680107
Bioessays. 1990 Sep;12(9):403-8
2256904
Development. 1999 Dec;126(24):5645-57
10572041
Plant Physiol. 2000 Jun;123(2):645-54
10859194
J Integr Plant Biol. 2009 Aug;51(8):740-50
19686371
Annu Rev Cell Dev Biol. 2001;17:159-87
11687487
PLoS One. 2009 May 29;4(5):e5744
19478943
Cell Mol Life Sci. 2004 Oct;61(19-20):2614-23
15526166
Plant Physiol. 2004 Dec;136(4):3968-78
15557099
Plant Cell. 2002 Oct;14(10):2613-26
12368508
Mol Biol Cell. 2007 Mar;18(3):827-38
17182858
Methods Enzymol. 2006;406:215-34
16472660
Planta. 2005 Apr;221(1):95-104
15747143
J Biol Chem. 2007 Sep 7;282(36):26528-41
17606613
Plant Physiol. 2000 Jan;122(1):35-48
10631247
Cell Motil Cytoskeleton. 1992;23(2):133-44
1333365
Plant Physiol. 1998 Apr;116(4):1421-9
9536060
J Cell Biol. 1987 Oct;105(4):1473-8
3312229
FEBS Lett. 2003 Sep 25;552(2-3):75-81
14527663
Science. 2009 Nov 27;326(5957):1208-12
19965462
Plant Cell. 1999 Dec;11(12):2349-63
10590163
J Exp Bot. 2010 Apr;61(7):1969-86
20159884
Biochemistry. 1984 Jun 5;23(12):2613-21
6432033
EMBO J. 1987 Dec 20;6(13):3901-7
3327686
Plant Cell. 1997 Nov;9(11):1999-2010
12237353
Mol Cell. 2006 Oct 6;24(1):13-23
17018289
J Biol Chem. 2001 Sep 28;276(39):36163-7
11500485
Cell Motil Cytoskeleton. 2009 Nov;66(11):940-57
19504571
Plant Cell. 2010 Aug;22(8):2727-48
20807878
J Biol Chem. 2007 Nov 16;282(46):33599-33608
17827159
Planta. 2000 Apr;210(5):836-43
10805457
Curr Opin Plant Biol. 2007 Dec;10(6):549-56
17936064
Curr Opin Plant Biol. 2006 Dec;9(6):554-62
17011229
J Cell Biol. 1979 Dec;83(3):667-73
574874
Biochem Biophys Res Commun. 1998 Aug 10;249(1):61-5
9705832
Proc Natl Acad Sci U S A. 1979 May;76(5):2321-5
287075
Cell. 1994 Jul 29;78(2):291-301
8044841