Plant Actin Biology


Actin is a major component of the plant cytoskeleton. Filamentous actin (F‐actin) contributes to the maintenance of the internal architecture of the cell, drives cytoplasmic streaming (the movement of components around the cytosol) and contributes to the process of cell division. The biochemistry of plant actin has many similarities to that of yeast and animals, but has developed its own strategies and molecular machinery to organise actin filaments. F‐actin provides tracks for myosin molecular motors to transport organelles at high velocities, and actin is required for specific stages of vesicle trafficking that underpin cell growth and development. The means by which plant cells control the nucleation of new actin filaments from G‐actin have diverged considerably from yeast and metazoans. The unique aspects of the plant actin cytoskeleton are likely to have arisen from a combination of the environmental challenges to a sessile multicellular existence and an ancient diversification from the ancestors of the Opisthokonta and Amoebozoa model organisms from which the majority of eukaryote cytoskeletal paradigms have been established.

Key Concepts

  • The basic principles of actin biochemistry applicable to animals, fungi and protists are conserved in plants but there are a number of specific modifications as plants do not possess the full complement of animal actin‐binding proteins.
  • Actin filaments in plants have to fulfil unique functions. Actin focuses on the expansion of tip growing cells, maintains cytoarchitecture and responds to the environment (e.g. polarising in response to pathogen stimulation). During cell division actin filaments participate in all major plant‐specific arrays.
  • A stationary cell is NOT a physically inactive cell. Actin cables are exploited for organelle transport. Actin‐based transport tends to dominate over microtubule‐based movement. Plants utilise the fastest known type V myosin (known in plants as type XI) within the eukaryote kingdom. Polymerisation dynamics are thought to add to trafficking capabilities as low levels of antiactin drugs disrupt vesicle delivery and fusion during cell growth yet preserve myosin‐mediated transport.
  • Plant‐specific proteins and novel domain combinations have become established in plants to regulate the actin cytoskeleton in accordance with the demands of sessile multicellular photosynthetic autotrophy. These cytoskeletal adaptations to sedentary life within a cell wall are distinct from fungi, possibly reflecting the ancient diversification between the opisthokonts and plants.

Keywords: actin; myosin; plant; microtubules; trafficking

Figure 1. The current molecular model for the dynamic instability of plant actin. The majority of monomeric globular actin (G‐actin; grey rectangles) in the plant cytoplasm is complexed with profilin. In pollen, profilin concentration is equimolar to actin. When ATP‐actin is bound to profilin the spontaneous nucleation of new filaments is prohibited, but sequestered actin can be added to uncapped barbed ends and nucleation factors such as formins can access the profilin–actin complexes to initiate new filaments. Actin filaments (F‐actin; in grey) are then organised into higher‐order structures by a variety of bundling, cross linking and severing proteins. After ATP hydrolysis and phosphate release actin depolymerising factor (ADF; coloured red) binds to F‐actin and accelerates subunit release from the pointed end. Actin monomers exchange ADP for ATP; actin purified from pollen has 20 times the nucleotide exchange activity of skeletal muscle actin. This process is augmented by the action of cyclase‐associated protein (CAP). Barbed ends are marked ‘+’ and pointed ends are marked ‘−’.
Figure 2. Filamentous actin in a plant cell. (a) Full projection of an image stack captured using a confocal laser‐scanning microscope. A Nicotiana tabacum BY2 tissue culture cell is shown expressing GFP fused to the second actin‐binding domain of fimbrin. The fimbrin domain associates with F‐actin, localising GFP fluorescence to the actin filaments within the cytoplasm. (b) Partial projection of the same image stack showing the volume occupied by the central vacuole. A cytoplasmic strand supported by a thick actin cable is visible (marked by asterisk). (c) Blue/red stereo image and full projection of the same cell. Scale bar is 20 µm.
Figure 3. Simple schematic of F‐actin distribution within typical plant cells. Concentrations of actin filaments are represented by blue lines. At interphase actin filaments can be observed throughout the cytoplasm. Prominent actin cables support cytoplasmic strands and encapsulate the nucleus (labelled ‘N’). Chloroplasts (labelled ‘C’) are anchored by the actin–myosin system and may have the capability to remodel the local network (see main text). The round inset illustrates the association of small organelles such as mitochondria, peroxisomes and Golgi stacks (labelled ‘G’) with actin via active myosin motors. In lower plants the cytoplasmic stream can reach speeds of 100 µm s−1. The endoplasmic reticulum (labelled ‘ER’) is also associated with the actin cytoskeleton. The rectangular insert illustrates the requirement for actin for some routes of post‐Golgi transport to the plasma membrane. The recycling of proteins from the plasma membrane through early endosomes (labelled ‘E’) also requires an intact actin cytoskeleton (see main text for details). During pre‐prophase the actin cytoskeleton coaligns with microtubules (represented by red lines) in a circular cortical array known as the preprophase band (PPB). The PPB is disassembled immediately prior to the formation of the spindle, and an actin depleted zone (ADZ) appears in the same region at the cell cortex. Subpopulations of F‐actin have been observed associated with the microtubule spindle (Traas et al., ; Yasuda et al., ) and are represented by dashed blue lines. At telophase the growing cell plate is sandwiched between an array of actin filaments and microtubules called the phragmoplast. This array can form in the absence of F‐actin but the rate of cell plate growth and the final disassembly of the microtubule component of the phragmoplast are enhanced by the actin cytoskeleton. The new cell plate finally fuses with the ADZ.


Allwood E, Anthony R, Smertenko A, et al. (2002) Regulation of the pollen‐specific actin‐depolymerizing factor LlADF1. Plant Cell 14: 2915–2927.

Bai Z and Grant BD (2015) A TOCA/CDC‐42/PAR/WAVE functional module required for retrograde endocytic recycling. Proceedings of the National Academy of Sciences 112: E1443–E1452.

Bannigan A, Wiedemeier AM, Williamson RE, Overall RL and Baskin TI (2006) Cortical microtubule arrays lose uniform alignment between cells and are oryzalin resistant in the Arabidopsis mutant, radially swollen 6. Plant and Cell Physiology 47: 949–958.

Boutté Y, Crosnier MT, Carraro N, Traas J and Satiat‐Jeunemaitre B (2006) The plasma membrane recycling pathway and cell polarity in plants: studies on PIN proteins. Journal of Cell Science 119: 1255–1265.

Cao L, Henty‐Ridilla JL, Blanchoin L and Christopher J (2016) Profilin‐dependent nucleation and assembly of actin filaments controls cell elongation in Arabidopsis. Plant Physiology 170: 220–233.

Chan J, Calder G, Fox S and Lloyd C (2007) Cortical microtubule arrays undergo rotary movements in Arabidopsis hypocotyl epidermal cells. Nature Cell Biology 9: 171–175.

Chaudhry F, Guérin C, von Witsch M, Blanchoin L and Staiger CJ (2007) Identification of Arabidopsis cyclase‐associated protein 1 as the first nucleotide exchange factor for plant actin. Molecular Biology of the Cell 18: 3002–3014.

Chen B, Brinkmann K, Chen Z, et al. (2014) The WAVE regulatory complex links diverse receptors to the actin cytoskeleton. Cell 156: 195–207.

Deeks MJ, Kaloriti D, Davies B, Malho R and Hussey PJ (2004) Arabidopsis NAP1 is essential for Arp2/3‐dependent trichome morphogenesis. Current Biology 14: 1410–1444.

Deeks MJ, Rodrigues C, Dimmock S, et al. (2007) Arabidopsis CAP1 – a key regulator of actin organisation and development. Journal of Cell Science 120: 2609–2618.

Deeks MJ, Calcutt JR, Ingle EKS, et al. (2012) A superfamily of actin‐binding proteins at the actin‐membrane nexus of higher plants. Current Biology 22: 1595–1600.

Fu Y, Wu G and Yang Z (2001) Rop GTPase‐dependent dynamics of tip‐localized F‐actin controls tip growth in pollen tubes. Journal of Cell Biology 152: 1019–1032.

Fu Y, Gu Y, Zheng Z, Wasteneys G and Yang Z (2005) Arabidopsis interdigitating cell growth requires two antagonistic pathways with opposing action on cell morphogenesis. Cell 120: 687–700.

Geldner N, Friml J, Stierhof Y, Jurgens G and Palme K (2001) Auxin transport inhibitors block PIN1 cycling and vesicle trafficking. Nature 413: 425–428.

Gibbon BC, Kovar DR and Staiger CJ (1999) Latrunculin B has different effects on pollen germination and tube growth. Plant Cell 11: 2349–2363.

Grebe M, Xu J, Möbius W, et al. (2003) Arabidopsis sterol endocytosis involves actin‐mediated trafficking via ARA6‐positive early endosomes. Current Biology 13: 1378–1387.

Hasezawa S, Sano T and Nagata T (1998) The role of microfilaments in the organization and orientation of microtubules during the cell cycle transition from M to G1 phase in tobacco BY‐2 cells. Protoplasma 202: 105–114.

He D, Fiz‐Palacios O, Fu CJ, et al. (2014) An alternative root for the eukaryote tree of life. Current Biology 24: 465–470.

Kandasamy M, McKinney E and Meagher R (2002) Functional nonequivalency of actin isovariants in Arabidopsis. Molecular Biology of the Cell 13: 251–261.

Kandasamy MK, Burgos‐Rivera B, McKinney EC, Ruzicka DR and Meagher RB (2007) Class‐specific interaction of profilin and ADF isovariants with actin in the regulation of plant development. Plant Cell 19: 3111–3126.

Kandasamy MK, McKinney EC, Roy E and Meagher RB (2012) Plant vegetative and animal cytoplasmic actins share functional competence for spatial development with protists. Plant Cell 24: 2041–2057.

Ketelaar T, de Ruijter N and Emons A (2003) Unstable F‐actin specifies the area and microtubule direction of cell expansion in Arabidopsis root hairs. Plant Cell 15: 285–292.

Ketelaar T, Allwood E, Anthony R, et al. (2004) The actin‐interacting protein AIP1 is essential for actin organization and plant development. Current Biology 14: 145–149.

Kim H, Park M, Kim S and Hwang I (2005) Actin filaments play a critical role in vacuolar trafficking at the Golgi complex in plant cells. Plant Cell 17: 888–902.

Kimura Y, Toyoshima N, Hirakawa N, Okamoto K and Ishijima A (2003) A kinetic mechanism for the fast movement of Chara myosin. Journal of Molecular Biology 328: 939–950.

Kovar D, Drobak B and Staiger CJ (2000) Maize profilin isoforms are functionally distinct. Plant Cell 12: 583–598.

Kovar D, Drobak B, Collings D and Staiger CJ (2001a) The characterization of ligand‐specific maize (Zea mays) profilin mutants. Biochemical Journal 358: 49–57.

Kovar D, Gibbon B, McCurdy D and Staiger CJ (2001b) Fluorescently‐labeled fimbrin decorates a dynamic actin filament network in live plant cells. Planta 213: 390–395.

Michelot A, Derivery E, Paterski‐Boujemaa R, et al. (2006) A novel mechanism for the formation of actin‐filament bundles by a nonprocessive formin. Current Biology 16: 1924–1930.

Müssar KJ, Kandasamy MK, McKinney EC and Meagher RB (2015) Arabidopsis plants deficient in constitutive class profilins reveal independent and quantitative genetic effects. BMC Plant Biology 15: 177.

Oikawa K, Kasahara M, Kiyosue T, et al. (2003) Chloroplast unusual positioning1 is essential for proper chloroplast positioning. Plant Cell 15: 2805–2815.

Ren H, Gibbon B, Ashworth S, et al. (1997) Actin purified from maize pollen functions in living plant cells. Plant Cell 9: 1445–1457.

Richards TA and Cavalier‐Smith T (2005) Myosin domain evolution and the primary divergence of eukaryotes. Nature 436: 1113–1118.

Rocchetti A, Hawes C and Kriechbaumer V (2014) Fluorescent labelling of the actin cytoskeleton in plants using a cameloid antibody. Plant Methods 10: 12.

Romagnoli S, Cai G, Faleri C, et al. (2007) Microtubule‐ and actin filament‐dependent motors are distributed on pollen tube mitochondria and contribute differently to their movement. Plant and Cell Physiology 48: 345–361.

Romero S, Le Clainche C, Didry D, et al. (2004) Formin is a processive motor that requires profilin to accelerate actin assembly and associated ATP hydrolysis. Cell 119: 419–429.

Schmidt von Braun S and Schleiff E (2008) The chloroplast outer membrane protein CHUP1 interacts with actin and profilin. Planta 227: 1151–1159.

Smertenko A, Deeks MJ and Hussey PJ (2010) Strategies of actin reorganisation in plant cells. Journal of Cell Science 123: 3019–3028.

Smith SA, Cranston KA, Allman JF, et al. (2015) Synthesis of phylogeny and taxonomy into a comprehensive tree of life. Proceedings of the National Academy of Sciences 112: 12764–12769.

Staiger CJ, Sheahan MB, Khurana P, et al. (2009) Actin filament dynamics are dominated by rapid growth and severing activity in the Arabidopsis cortical array. Journal of Cell Biology 184: 269–280.

Suarez C, Carroll RT, Burke TA, et al. (2015) Profilin regulates F‐actin network homeostasis by favoring formin over Arp2/3 complex. Developmental Cell 32: 43–53.

Tominaga M, Yokota E, Vidali L, et al. (2000) The role of plant villin in the organization of the actin cytoskeleton, cytoplasmic streaming and the architecture of the transvacuolar strand in root hair cells of Hydrocharis. Planta 210: 836–843.

Traas JA, Doonan JH, Rawlins DJ, et al. (1987) An actin network is present in the cytoplasm throughout the cell cycle of carrot cells and associates with the dividing nucleus. Journal of Cell Biology 105: 387–395.

Uhrig JF, Mutondo M, Zimmermann I, et al. (2007) The role of Arabidopsis SCAR genes in ARP2‐ARP3‐dependent cell morphogenesis. Development 134: 967–977.

Wang P, Hawkins TJ, Richardson C, et al. (2014) The plant cytoskeleton, NET3C, and VAP27 mediate the link between the plasma membrane and endoplasmic reticulum. Current Biology 24: 1397–1405.

Yasuda H, Kanda K, Koiwa H, et al. (2005) Localization of actin filaments on mitotic apparatus in tobacco BY‐2 cells. Planta 222: 118–129.

Yoneda A, Akatsuka M, Hoshino H, Kumagai F and Hasezawa S (2005) Decision of spindle poles and division plane by double preprophase bands in a BY‐2 cell line expressing GFP‐tubulin. Plant and Cell Physiology 46: 531–538.

Zhang C, Mallery EL, Schlueter J, et al. (2008) Arabidopsis SCARs function interchangeably to meet actin‐related protein 2/3 activation thresholds during morphogenesis. Plant Cell 20: 995–1011.

Further Reading

Canut H, Carrasco A, Galaud JP, et al. (1998) High affinity RGD‐binding sites at the plasma membrane of Arabidopsis thaliana links the cell wall. Plant Journal 16: 63–71.

Cavalier‐Smith T (2009) Predation and eukaryote cell origins: a coevolutionary perspective. International Journal of Biochemistry and Cell Biology 41: 307–322.

Deeks MJ, Cvrcková F, Machesky LM, et al. (2005) Arabidopsis group Ie formins localize to specific cell membrane domains, interact with actin‐binding proteins and cause defects in cell expansion upon aberrant expression. New Phytologist 168: 529–540.

Elliott DA, McIntosh MT, Hosgood HD, et al. (2008) Four distinct pathways of hemoglobin uptake in the malaria parasite Plasmodium falciparum. Proceedings of the National Academy of Sciences of the United States of America 105: 2463–2468.

Hamada T (2007) Microtubule‐associated proteins in higher plants. Journal of Plant Research 120: 79–98.

Hawkins TJ, Deeks MJ, Wang P and Hussey PJ (2014) The evolution of the actin binding NET superfamily. Frontiers in Plant Science 254. DOI: 10.3389/fpls.2014.00254.

Higgs HN and Pollard TD (2001) Regulation of actin filament network formation through ARP2/3 complex: activation by a diverse array of proteins. Annual Reviews of Biochemistry 70: 649–676.

Hoshino H, Yoneda A, Kumagai F and Hasezawa S (2003) Roles of actin‐depleted zone and preprophase band in determining the division site of higher‐plant cells, a tobacco BY‐2 cell line expressing GFP‐tubulin. Protoplasma 222: 157–165.

Huang S, Robinson R, Gao L, et al. (2005) Arabidopsis VILLIN1 generates actin filament cables that are resistant to depolymerization. Plant Cell 17: 486–501.

Hussey PJ, Ketelaar T and Deeks MJ (2006) Control of the actin cytoskeleton in plant cell growth. Annual Reviews of Plant Biology 57: 109–125.

Innocenti M, Gerboth S, Rottner K, et al. (2005) Abi1 regulates the activity of N‐WASP and WAVE in distinct actin‐based processes. Nature Cell Biology 7: 969–976.

Kandasamy MK, McKinney EC and Meagher RB (2009) A single vegetative actin isovariant overexpressed under the control of multiple regulatory sequences is sufficient for normal Arabidopsis development. The Plant Cell 21: 701–718.

Lassing I and Lindberg U (1985) Specific interaction between phosphatidylinositol 4,5‐bisphosphate and profilactin. Nature 314: 472–474.

Mathur J, Spielhofer P, Kost B and Chua N (1999) The actin cytoskeleton is required to elaborate and maintain spatial patterning during trichome cell morphogenesis in Arabidopsis thaliana. Development 126: 5559–5568.

Paredez AR, Somerville CR and Ehrhardt DW (2006) Visualization of cellulose synthase demonstrates functional association with microtubules. Science 312: 1491–1495.

Runions J, Brach T, Kühner S and Hawes CJ (2006) Photoactivation of GFP reveals protein dynamics within the endoplasmic reticulum membrane. Journal of Experimental Botany 57: 43–50.

Staiger CJ, Baluska F and Volkmann D (eds) (2000) Actin: A Dynamic Framework for Multiple Plant Cell Functions. New York: Springer‐Verlag.

Szymanski DB, Marks MD and Wick SM (1999) Organized F‐actin is essential for normal trichome morphogenesis in Arabidopsis. Plant Cell 11: 2331–2347.

Takemoto D, Jones DA and Hardham AR (2003) GFP‐tagging of cell components reveals the dynamics of subcellular re‐organization in response to infection of Arabidopsis by oomycete pathogens. Plant Journal 33: 775–792.

Wang P and Hussey PJ (2015) Interactions between plant endomembrane systems and the actin cytoskeleton. Frontiers in Plant Science. 6: 422.

Van Damme D, Vanstraelen M and Geelen D (2007) Cortical division zone establishment in plant cells. Trends in Plant Science 12: 458–464.

Yang Z (2008) Cell polarity signaling in Arabidopsis. Annual Review of Cell and Developmental Biology 24: 551–575.

Contact Editor close
Submit a note to the editor about this article by filling in the form below.

* Required Field

How to Cite close
Deeks, Michael J, and Hussey, Patrick J(Jul 2016) Plant Actin Biology. In: eLS. John Wiley & Sons Ltd, Chichester. [doi: 10.1002/9780470015902.a0021255.pub2]