Tomato SP-Interacting Proteins Define a Conserved Signaling System That Regulates Shoot Architecture and Flowering

Pnueli, Lilac; Gutfinger, Tamar; Hareven, Dana; Ben-Naim, Orna; Ron, Neta; Adir, Noam; Lifschitz, Eliezer

doi:10.2307/3871528

Cited by 68 publications

(104 citation statements)

References 55 publications

(92 reference statements)

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“…6). 5F) and was reported to be a mobile signal that mediates the transition to flowering (41,42). CLV proteins are responsible for controlling the size of the SAM; they restrict the population of stem cells by limiting the expression of the transcription factor WUSCHEL (WUS) in the peripheral zone of the meristem (36,43,44).…”

Section: Resultsmentioning

confidence: 99%

The shoot meristem identity gene TFL1 is involved in flower development and trafficking to the protein storage vacuole

Sohn

Rojas-Pierce

Pan

et al. 2007

Proc. Natl. Acad. Sci. U.S.A.

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Plants are unique in their ability to store proteins in specialized protein storage vacuoles (PSVs) within seeds and vegetative tissues. Although plants use PSV proteins during germination, before photosynthesis is fully functional, the roles of PSVs in adult vegetative tissues are not understood. Trafficking pathways to PSVs and lytic vacuoles appear to be distinct. Lytic vacuoles are analogous evolutionarily to yeast and mammalian lysosomes. However, it is unclear whether trafficking to PSVs has any analogy to pathways in yeast or mammals, nor is PSV ultrastructure known in Arabidopsis vegetative tissue. Therefore, alternative approaches are required to identify components of this pathway. Here, we show that an Arabidopsis thaliana mutant that disrupts PSV trafficking identified TERMINAL FLOWER 1 (TFL1), a shoot meristem identity gene. The tfl1-19/mtv5 (for ''modified traffic to the vacuole'') mutant is specifically defective in trafficking of proteins to the PSV. TFL1 localizes to endomembrane compartments and colocalizes with the putative ␦-subunit of the AP-3 adapter complex. Our results suggest a developmental role for the PSV in vegetative tissues.protein trafficking ͉ vegetative tissue ͉ adaptin

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Section: Resultsmentioning

confidence: 99%

The shoot meristem identity gene TFL1 is involved in flower development and trafficking to the protein storage vacuole

Sohn

Rojas-Pierce

Pan

et al. 2007

Proc. Natl. Acad. Sci. U.S.A.

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“…Overexpression of other cell cycle-related proteins has also been shown to affect the morphology of floral organs, including the ectopic expression of ICK1, a CDK inhibitor in Arabidopsis, which showed drastic growth and cell division inhibition [39]. As well, both the antisense expression of the tomato SPAK and the ectopic expression of its C-terminal extension resulted in the formation of pear-shaped fruits [10].…”

Section: Discussionmentioning

confidence: 99%

“…AmnimA was recovered as a partial 500 bp fragment in the catalytic kinase domain [9]. SPAK was shown to interact with SP, a 23-kDa protein involved in shoot architecture and flowering regulation [10]. SPAK was also found to interact with 14-3-3 isoforms and self-pruning interacting protein 4 (SIP4) a novel 10 kDa protein.…”

Section: Introductionmentioning

confidence: 99%

Characterization of a poplar NIMA‐related kinase PNek1 and its potential role in meristematic activity

et al. 2005

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Meristems are sites of undifferentiated cell division, which carry on developing into functional organs. Using the two-hybrid system with a poplar 14-3-3, we uncovered poplar NIMA-related kinase 1 (PNek1) as an interacting protein.PNek1 shows high homology to the mammalian NIMA-related kinases, which are thought to be involved in cell cycle progression. Using a synchronized poplar cell suspension, we observed an accumulation of PNek1 mRNA at the G 1 /S transition and throughout the G 2 -to-M progression. Moreover, PNek1-GFP fusion protein localized in the cytoplasm and in both the nuclear and nucleolar regions. Overexpression of PNek1-GFP in Arabidopsis caused morphological abnormalities in flower and siliques. Overall, these results suggest that PNek1 is involved in plant development.

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“…In contrast, induction of TFL1 results in a suppression of flowering (6,7,17,18). Genetic analyses show that TFL1 and FT act independently in flowering control but, so far, studies in different plant species have not revealed the biochemical mechanism of this family of proteins (8,9,11,(13)(14)(15)(22)(23)(24).TFL1 and FT are homologous to phosphatidylethanolaminebinding proteins (PEBPs), a wider group of proteins that have diverse roles in animals, yeast, and bacteria. The PEBP family regulates signaling pathways to control growth and differentiation.…”

mentioning

confidence: 99%

A single amino acid converts a repressor to an activator of flowering

Hanzawa

Money

Bradley

2005

Proc. Natl. Acad. Sci. U.S.A.

445

428

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Homologous proteins occurring through gene duplication may give rise to novel functions through mutations affecting protein sequence or expression. Comparison of such homologues allows insight into how morphological traits evolve. However, it is often unclear which changes are key to determining new functions. To address these ideas, we have studied a system where two homologues have evolved clear and opposite functions in controlling a major developmental switch. In plants, flowering is a major developmental transition that is critical to reproductive success. Arabidopsis phosphatidylethanolamine-binding protein homologues TERMINAL FLOWER 1 (TFL1) and FLOWERING LOCUS T (FT) are key controllers of flowering, determining when and where flowers are made, but as opposing functions: TFL1 is a repressor, FT is an activator. We have uncovered a striking molecular basis for how these homologous proteins have diverged. Although <60% identical, we have shown that swapping a single amino acid is sufficient to convert TFL1 to FT function and vice versa. Therefore, these key residues may have strongly contributed to the selection of these important functions over plant evolution. Further, our results suggest that TFL1 and FT are highly conserved in biochemical function and that they act as repressors or activators of flowering through discrimination of structurally related interactors by a single residue. FLOWERING LOCUS T ͉ phosphatidylethanolamine-binding protein ͉Raf-kinase inhibitor protein ͉ TERMINAL FLOWER 1 N ovel morphologies arise through the evolution of new protein functions. Duplicated genes are a key source of new functions, acquiring mutations that affect expression and͞or protein sequence (1, 2). Studies of large gene families show that different members diverge and participate in different developmental pathways, for example, homeobox and MADS box genes in various species (3-5). However, it is often unclear and difficult to determine which changes in homologues are critical to establish a novel function.The Arabidopsis homologues TERMINAL FLOWER 1 (TFL1) and FLOWERING LOCUS T (FT) provide an excellent model to address this question (6-9). Flowering plant species arose Ͼ 100 million years ago, and FT and TFL1 have been conserved in diverse species, including monocots and eudicots (10-15). Both TFL1 and FT are key controllers of flowering and plant architecture but act in an opposite manner. TFL1 is a repressor, and FT is an activator. Further, gain-of-function studies gave clear and opposite phenotypes in vivo, showing that protein sequence, rather than expression pattern, largely determines the different functions of TFL1 and FT (8,9,16).TFL1 is expressed in the shoot apical meristem (SAM) and represses the transition to flowering; tfl1 mutants flower early (6,7,17,18). TFL1 also maintains indeterminate growth of the SAM by repressing floral meristem identity genes; tfl1 mutants have their SAMs converted into terminal flowers. TFL1 therefore controls plant architecture by determining where flowers are made a...

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Tomato SP-Interacting Proteins Define a Conserved Signaling System That Regulates Shoot Architecture and Flowering

Cited by 68 publications

References 55 publications

The shoot meristem identity gene TFL1 is involved in flower development and trafficking to the protein storage vacuole

The shoot meristem identity gene TFL1 is involved in flower development and trafficking to the protein storage vacuole

Characterization of a poplar NIMA‐related kinase PNek1 and its potential role in meristematic activity

A single amino acid converts a repressor to an activator of flowering

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