Font Size: a A A

The Juxtamembrane And Carboxy-terminal Domains Of Arabidopsis PRK2Are Critical For ROP-induced Growth In Pollen Tubes

Posted on:2015-11-30Degree:MasterType:Thesis
Country:ChinaCandidate:Q WangFull Text:PDF
GTID:2180330431473564Subject:Cell biology
Abstract/Summary:PDF Full Text Request
Polarized growth of pollen tubes is a critical step for successful reproduction in angiosperms and is controlled by ROP GTPases. Spatiotemporal activation of ROP (Rho GTPases of plants) necessitates a complex and sophisticated regulatory system, in which guanine nucleotide exchange factors (RopGEFs) are key components. It was previously shown that a leucine-rich repeat receptor-like kinase, Arabidopsis pollen receptor kinase2(AtPRK2), interacted with RopGEF12for its membrane recruitment. However, the mechanisms underlying AtPRK2-mediated ROP activation in vivo are yet to be defined. It is reported here that over-expression of AtPRK2induced tube bulging that was accompanied by the ectopic localization of ROP-GTP and the ectopic distribution of actin microfilaments. Tube depolarization was also induced by a potentially kinase-dead mutant, AtPRK2K366R, suggesting that the over-expression effect of AtPRK2did not require its kinase activity. By contrast, deletions of non-catalytic domains in AtPRK2, i.e. the juxtamembrane (JM) and carboxy-terminal (CT) domains, abolished its ability to affect tube polarization. Notably, AtPRK2K366R retained the ability to interact with RopGEF12, whereas AtPRK2truncations of these non-catalytic domains did not. Lastly, it has been shown that the JM and CT domains of AtPRK2were not only critical for its interaction with RopGEF12but also critical for its distribution at the plasma membrane. These results thus provide further insight into pollen receptor kinase-mediated ROP activation during pollen tube growth.
Keywords/Search Tags:Actin microfilaments, CRIB, polar growth, receptor kinase, ROP GTPases
PDF Full Text Request
Related items