STIL, a peculiar molecule from styles, specifically dephosphorylates the pollen receptor kinase LePRK2 and stimulates pollen tube growth in vitro

WENGIER, DIEGO; MAZZELLA, MARIA AGUSTINA; SALEM, TAMARA; MCCORMICK, SHEILA; MUSCHIETTI, JORGE

BMC PLANT BIOLOGY

BIOMED CENTRAL LTD

Año: 2010 vol. 10 p. 1 - 11

1471-2229

<!-- /* Font Definitions */ @font-face {font-family:Tahoma; panose-1:2 11 6 4 3 5 4 4 2 4; mso-font-charset:0; mso-generic-font-family:auto; mso-font-pitch:variable; mso-font-signature:3 0 0 0 1 0;} @font-face {font-family:PMingLiU; mso-font-alt:新細明體; mso-font-charset:136; mso-generic-font-family:roman; mso-font-pitch:variable; mso-font-signature:-1610611969 684719354 22 0 1048577 0;} /* Style Definitions */ p.MsoNormal, li.MsoNormal, div.MsoNormal {mso-style-parent:""; margin:0cm; margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:Tahoma; mso-ascii-font-family:"Times New Roman"; mso-fareast-font-family:PMingLiU; mso-hansi-font-family:"Times New Roman"; mso-bidi-font-family:Tahoma; mso-ansi-language:ES-AR; mso-fareast-language:ZH-TW;} @page Section1 {size:612.0pt 792.0pt; margin:72.0pt 90.0pt 72.0pt 90.0pt; mso-header-margin:36.0pt; mso-footer-margin:36.0pt; mso-paper-source:0;} div.Section1 {page:Section1;} --> 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 protease-resistant 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 ~3550 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 dose-dependent manner. Conclusions We propose that the LePRK complex perceives STIL, resulting in LePRK2 dephosphorylation and an increase in pollen tube growth.