|Wengier, Diego l.|
|Mazzeklla, Maria a.|
|Salem, Tamara m.|
|Muschietti, Jorge p.|
Submitted to: Biomed Central (BMC) Plant Biology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 2/22/2010
Publication Date: 2/22/2010
Publication URL: www.biomedcentral.com/content/pdf/1471-2229-10-33.pdf
Citation: Wengier, D., Mazzeklla, M., Salem, T., Mccormick, S.M., Muschietti, J. 2010. STIL, a peculiar molecule from styles, specifically dephosphorylates the pollen receptor kinase LePRK2 and stimulates pollen tube growth in vitro. Biomed Central (BMC) Plant Biology. Online 1471-2229/10/33. Interpretive Summary: LePRK2 is a pollen receptor kinase that is dephosphorylated when incubated with style extracts. Here we show that LePRK2 dephosphorylation is mediated by a highly resistant molecule from styles, that we named STIL (for Style Interactor for LePRKs). STIL increased pollen tube lengths of in vitro germinated pollen.
Technical Abstract: BACKGROUND: LePRK1 and LePRK2 are two pollen receptor kinases localized to the plasma membrane, where they are present in a high molecular weight complex (LePRK complex). LePRK2 is phosphorylated in mature and germinated pollen, but is dephosphorylated when pollen membranes are incubated with tomato or tobacco style extracts. RESULTS: Here we show that LePRK2 dephosphorylation is mediated by a heat-, acid-, base-, DTT- and proteaseresistant component from tobacco styles. Using LePRK2 phosphorylation as a tracking assay for purification, style exudates were subjected to chloroform extraction, anionic exchange, and C18 reverse-phase chromatography columns. We finally obtained a single ~3,550 Da compound (as determined by UV-MALDI-TOF MS) that we named STIL (for Style Interactor for LePRKs). STIL increased pollen tube lengths of in vitro germinated pollen in a dosedependent manner. CONCLUSION: We propose that the LePRK complex perceives STIL, resulting in LePRK2 dephosphorylation and an increase in pollen tube growth.