An extracellular transglutaminase is required for apple pollen tube growth.
نویسندگان
چکیده
An extracellular form of the calcium-dependent protein-cross-linking enzyme TGase (transglutaminase) was demonstrated to be involved in the apical growth of Malus domestica pollen tube. Apple pollen TGase and its substrates were co-localized within aggregates on the pollen tube surface, as determined by indirect immunofluorescence staining and the in situ cross-linking of fluorescently labelled substrates. TGase-specific inhibitors and an anti-TGase monoclonal antibody blocked pollen tube growth, whereas incorporation of a recombinant fluorescent mammalian TGase substrate (histidine-tagged green fluorescent protein: His6-Xpr-GFP) into the growing tube wall enhanced tube length and germination, consistent with a role of TGase as a modulator of cell wall building and strengthening. The secreted pollen TGase catalysed the cross-linking of both PAs (polyamines) into proteins (released by the pollen tube) and His6-Xpr-GFP into endogenous or exogenously added substrates. A similar distribution of TGase activity was observed in planta on pollen tubes germinating inside the style, consistent with a possible additional role for TGase in the interaction between the pollen tube and the style during fertilization.
منابع مشابه
Regulation of Pollen Tube Growth by Transglutaminase.
In pollen tubes, cytoskeleton proteins are involved in many aspects of pollen germination and growth, from the transport of sperm cells to the asymmetrical distribution of organelles to the deposition of cell wall material. These activities are based on the dynamics of the cytoskeleton. Changes to both actin filaments and microtubules are triggered by specific proteins, resulting in different o...
متن کاملA cysteine-rich extracellular protein, LAT52, interacts with the extracellular domain of the pollen receptor kinase LePRK2.
Pollen germination and pollen tube growth are thought to require extracellular cues, but how these cues are perceived and transduced remains largely unknown. Pollen receptor kinases are plausible candidates for this role; they might bind extracellular ligands and thereby mediate cytoplasmic events required for pollen germination and pollen tube growth. To search for pollen-expressed ligands for...
متن کاملThe pollen receptor kinase LePRK2 mediates growth-promoting signals and positively regulates pollen germination and tube growth.
In flowering plants, the process of pollen germination and tube growth is required for successful fertilization. A pollen receptor kinase from tomato (Solanum lycopersicum), LePRK2, has been implicated in signaling during pollen germination and tube growth as well as in mediating pollen (tube)-pistil communication. Here we show that reduced expression of LePRK2 affects four aspects of pollen ge...
متن کاملPollen-pistil interactions in compatible pollination.
Plant sexual reproduction depends on highly specific interactions between pollen and pistil, the male gametophyte and the female reproductive organ, respectively (1, 2). The pistil is composed of three major structural parts: the stigma, the style, and the ovary. The stigma has a pollen-receptive surface and several underlying secretory cell layers. The style connects the stigma to the basally ...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- The Biochemical journal
دوره 429 2 شماره
صفحات -
تاریخ انتشار 2010