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The role of actin dynamics in auxin transport
Stillerová, Lenka ; Cvrčková, Fatima (advisor) ; Schwarzerová, Kateřina (referee)
Phytohormones are signalling molecules directing physiological and developmental processes in plants. One of them, auxin, is involved in the diverse regulation of plant processes, e.g. embryogenesis, organogenesis, vascular tissue formation and tropisms. Auxin transport is polar. Auxin isdistributed via the phloem, utilizing specialized membrane transport proteins; small amount diffuse also through the membrane. Aux1/Lax transporters mediate auxin entry into the cell, auxin efflux is mediate mostly by PIN transporters, which are the crucial factors in determining the directionality of auxin flow. Asymmetric localization of membrane PIN proteins depends on vesicle transport from Golgi to the plasma membrane. Vesicles are transported along actin filaments which are dynamically rebuilted by regulators. They are maintaining asymmetric cellular localization of the auxin transport proteins. PIN proteins are cycling between endosomes and plasma membrane. Cycling is regulated by ARF-GEF proteins and serin/threonin kinase (PID, PINOID). Newly synthesized PIN proteins are equally distributed in the plasma membrane, afterwards they are asymmetrically redistributed. Regulation of actin filaments formation and remodelling is the crucial factor for transport of vesicles with PIN proteins. Many proteins which regulate...
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