Other effec tors such as amphiregulin and p21WAF1CIP1 also merit consideration to be targeted alone or in combination with other downstream molecules. Competing interests The authors declare that they have no competing interests. Background Actin cytoskeleton provides tracks for myosin medi ated movements of organelles in plant cells. The dynamic nature of the cytoskeleton www.selleckchem.com/products/U0126.html depends on actin binding proteins which control the assembly of actin fila ments and their organization into higher order structures. On the basis of AC, chloroplasts change their intracellular arrangement in response to light. These movements are controlled only by blue light in higher plants. Inhibitors,Modulators,Libraries Weak blue light induces an accumulation response in which chloroplasts gather along the cell walls perpendic ular to the light direction.

Strong blue light induces an avoidance response in which Inhibitors,Modulators,Libraries they stay at the walls par allel to the light direction, away from the most illumi nated parts of the cell. The light signal is perceived by phototropins, blue light photorecep tors localised at the plasma membrane. Both pho totropins mediate chloroplast accumulation, whereas phot2 mediates the avoidance response. Inhibitors,Modulators,Libraries Chloro plasts of several algae, mosses, ferns and aquatic angiosperms respond also to red light. Chloroplasts move along AFs using myosins associated with their membrane. Microtubules do not seem to be involved in the directional redistribution of chloro plasts in higher land plants. Inhibitors,Modulators,Libraries In spite of recent advances little is known about the pathway upon which the blue light signal is transmitted from phototropins to the motor apparatus.

Only two types of secondary messengers have been critically discussed in this context Ca2 ions and the phosphoinositide kinases. Calcium ions regulate the activity of many cytoskeletal Inhibitors,Modulators,Libraries proteins and act as secondary messenger in several plant signalling pathways including those initiated by pho totropins. As shown in studies employing the aequorin Ca2 reporter system, BL acting through phot1 induced an increase in cytosolic Ca2 in Arabidopsis and tobacco seedlings. Phototropin 1 was also responsi ble for triggering an influx of Ca2 across the plasma mem brane in Arabidopsis seedling hypocotyls and for activating Ca2 channels at the plasma membrane of Ara bidopsis mesophyll protoplasts.

Calcium ions have been postulated as a potential secondary messenger in red light controlled chloroplast movements and cytoplasmic streaming in the aquatic angiosperm, http://www.selleckchem.com/products/Belinostat.html Vallisneria gigantea. The function of Ca2 in BL induced movements still awaits clarification. Manipulating cytosolic calcium homeostasis with various calcium antagonists was shown to interfere with both wBL and SBL chloroplast responses. However, this does not explain the role calcium ions play in their mechanisms.