Unitary exocytotic and endocytotic events in <i>Zea mays</i> L. coleoptile protoplasts

Thiel, Gerhard; Kreft, Marko; Zorec, Robert

doi:10.1046/j.1365-313x.1998.00012.x

Cited by 33 publications

(16 citation statements)

References 22 publications

(50 reference statements)

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“…A similar secondary effect on ER-to-Golgi transport of secGFP was postulated when membrane traffic was inhibited with a dominant-inhibitory peptide derived from a syntaxin (Geelen et al, 2002) that resides at the PM (Leyman et al, 2000). A disadvantage of all trafficking assays based on transient expression of dominant-inhibitory proteins is that the protein accumulates to inhibitory levels over a period of hours, whereas trafficking of the marker takes place over much shorter time scales (Phillips et al, 1988;Thiel et al, 1998;Brandizzi et al, 2002b). This makes it difficult to distinguish primary from secondary effects on membrane traffic, and it will take the development of conditional mutants and assays for initial trafficking rates to overcome this limitation in plant cells.…”

Section: Discussionmentioning

confidence: 80%

A Rab-E GTPase Mutant Acts Downstream of the Rab-D Subclass in Biosynthetic Membrane Traffic to the Plasma Membrane in Tobacco Leaf Epidermis

et al. 2005

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The function of the Rab-E subclass of plant Rab GTPases in membrane traffic was investigated using a dominant-inhibitory mutant (RAB-E1 d [NI]) of Arabidopsis thaliana RAB-E1 d and in vivo imaging approaches that have been used to characterize similar mutants in the plant Rab-D2 and Rab-F2 subclasses. RAB-E1 d [NI] inhibited the transport of a secreted green fluorescent protein marker, secGFP, but in contrast with dominant-inhibitory RAB-D2 or RAB-F2 mutants, it did not affect the transport of Golgi or vacuolar markers. Quantitative imaging revealed that RAB-E1 d [NI] caused less intracellular secGFP accumulation than RAB-D2 a [NI], a dominant-inhibitory mutant of a member of the Arabidopsis Rab-D2 subclass. Furthermore, whereas RAB-D2 a [NI] caused secGFP to accumulate exclusively in the endoplasmic reticulum, RAB-E1 d [NI] caused secGFP to accumulate additionally in the Golgi apparatus and a prevacuolar compartment that could be labeled by FM4-64 and yellow fluorescent protein (YFP)-tagged Arabidopsis RAB-F2 b . Using the vacuolar protease inhibitor E64-d, it was shown that some secGFP was transported to the vacuole in control cells and in the presence of RAB-E1 d [NI]. Consistent with the hypothesis that secGFP carries a weak vacuolar-sorting determinant, it was shown that a secreted form of DsRed reaches the apoplast without appearing in the prevacuolar compartment. When fused to RAB-E1 d , YFP was targeted specifically to the Golgi via a saturable nucleotide-and prenylation-dependent mechanism but was never observed on the prevacuolar compartment. We propose that RAB-E1 d [NI] inhibits the secretory pathway at or after the Golgi, causing an accumulation of secGFP in the upstream compartments and an increase in the quantity of secGFP that enters the vacuolar pathway.

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Section: Discussionmentioning

confidence: 80%

A Rab-E GTPase Mutant Acts Downstream of the Rab-D Subclass in Biosynthetic Membrane Traffic to the Plasma Membrane in Tobacco Leaf Epidermis

et al. 2005

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“…Endocytosis is postulated to counterbalance membrane secretion (Samuels and Bialputra, 1990) and permit cell volume to respond to changes in osmolality (Thiel et al, 1998;Kubitscheck et al, 2000). However, the study of plant cell endocytosis has been hampered by the scarcity of markers that can be used in the presence of the plant cell wall (Low and Chandra, 1994;Buchanan et al, 2000).…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“…Endocytosed markers are proposed to enter plant cells via coated pit invagination and budding into the cytoplasm (Marcote et al, 2000). Electrophysiological studies indicate that early endocytic vesicles have a diameter between 70 and 100 nm (Thiel et al, 1998), and ultrastructural analysis has shown that the endocytic pathway, as in animal and yeast cells, consists of a series of structurally distinct organelles (Galway et al, 1993).The markers used to follow plant endocytosis have included heavy metal salts, lucifer yellow, and insoluble membrane markers (reviewed by Fowke et al, 1991;Oparka et al, 1991). The disadvantages are that these dyes may not be entirely cell impermeant and may enter by nonendocytic routes (O'Drisscoll et al, 1991), as has been shown for fluorescein isothiocyanate (Cole et al, 1990) and lucifer yellow (Wright and Oparka, 1989;Roszak and Rambour, 1997), or that the marker can be observed only by electron microscopy in fixed protoplasts, such as for cationized ferritin (Fowke et al, 1991;Galway et al, 1993).…”

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confidence: 99%

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Uptake of a Fluorescent Marker in Plant Cells Is Sensitive to Brefeldin A and Wortmannin

2002

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We assessed FM1-43 [ N -(3-triethylammoniumpropyl)-4-(4-[dibutylamino]styryl)pyridinium dibromide] as a fluorescent endocytosis marker in intact, walled plant cells. At 4 ؇ C, FM1-43 stained the plasma membrane, and after 30 to 120 min of incubation at 26 ؇ C, FM1-43 labeled cytoplasmic vesicles and then the vacuole. Fluorimetric quantitation demonstrated dye uptake temperature sensitivity ( ‫ف‬ 65% reduction at 16 ؇ C, Ͼ 90% at 4 ؇ C). FM1-43 uptake in suspension cells was stimulated more than twofold by brefeldin A and inhibited ‫ف‬ 0.4-fold by wortmannin. FM1-43 delivery to the vacuole was largely inhibited by brefeldin A, although overall uptake was stimulated, and brefeldin A treatment caused the accumulation of large prevacuolar endosomal vesicles heavily labeled with FM1-43. Three-dimensional time lapse imaging revealed that FM1-43-labeled vacuoles and vesicles are highly dynamic. Thus, FM1-43 serves as a fluorescent marker for imaging and quantifying membrane endocytosis in intact plant cells. INTRODUCTIONEndocytosis in animal cells begins with the budding of invaginated coated pits from the plasma membrane into coated vesicles, which then uncoat and fuse with the endocytic organelles (Gruenberg et al., 1989;Gruenberg and Maxfield, 1995). By this action, both membrane proteins and fluid phase molecules are sequestered from the cell exterior into intracellular organelles, from where they can recycle to the plasma membrane or be transported to other destinations, such as the lysosomes. Thus, endocytosis serves to balance membrane secretion and to remove, transport, or degrade receptor ligand complexes from the cell surface (Goldstein et al., 1985). Although clathrin coatdependent endocytosis is involved in receptor internalization, clathrin-independent endocytosis pathways also contribute to internalization. These include uptake via nonclathrin-coated caveolae (Anderson, 1998), macropinocytosis (Swanson, 1989;Hewlett et al., 1994), and phagocytosis (Aderem and Underhill, 1999).Our understanding of animal cell endocytosis was advanced by the use of fluorescent and electron-opaque markers that can be internalized Maxfield, 1988, 1989;Griffiths et al., 1989). The use of fluid phase markers has permitted the development of assays that reconstitute endocytic vesicle fusion (Braell, 1987(Braell, , 1992Gruenberg et al., 1989;Emans et al., 1995;Emans and Verkman, 1996) and led to the identification of many proteins that catalyze and control fusion, such as the small GTPase rab5 (Gorvel et al., 1991) and its effector proteins (Christoforidis et al., 1999a(Christoforidis et al., , 1999bMcBride et al., 1999).In plants, there is evidence that endocytosis is likely to occur (Low and Chandra, 1994; for review, see Battey et al., 1999;Marcote et al., 2000). Endocytosis is postulated to counterbalance membrane secretion (Samuels and Bialputra, 1990) and permit cell volume to respond to changes in osmolality (Thiel et al., 1998;Kubitscheck et al., 2000). However, the study of plant cell endocytosis has been hampered by t...

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“…In fully grown cells, the rate of exocytosis may be more or less equal to that of endocytosis; and, in aging cells, the rate of endocytosis likely exceeds that of exocytosis. 46,47 Future research will either confirm or reject these propositions, but it is clear that many more detailed measurements of metabolic rates are required and that current theoretical attempts to explain mechanistically why metabolic rates change with increasing body size are inadequate. [48][49][50][51][52][53] Finally, we want to stress that the exact regulatory mechanisms of O 2 -dependent Figure 8.…”

Section: Discussionmentioning

confidence: 99%

Kleiber's Law: How theFire of Lifeignited debate, fueled theory, and neglected plants as model organisms

Niklas¹,

Kutschera

2015

Plant Signaling & Behavior

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Size is a key feature of any organism since it influences the rate at which resources are consumed and thus affects metabolic rates. In the 1930s, size-dependent relationships were codified as "allometry" and it was shown that most of these could be quantified using the slopes of log-log plots of any 2 variables of interest. During the decades that followed, physiologists explored how animal respiration rates varied as a function of body size across taxa. The expectation was that rates would scale as the 2/3 power of body size as a reflection of the Euclidean relationship between surface area and volume. However, the work of Max Kleiber (1893Kleiber ( -1976 and others revealed that animal respiration rates apparently scale more closely as the 3/4 power of body size. This phenomenology, which is called "Kleiber's Law," has been described for a broad range of organisms, including some algae and plants. It has also been severely criticized on theoretical and empirical grounds. Here, we review the history of the analysis of metabolism, which originated with the works of Antoine L. Lavoisier (1743-1794) and Julius Sachs (1832-1897), and culminated in Kleiber's book The Fire of Life (1961; 2. ed. 1975). We then evaluate some of the criticisms that have been leveled against Kleiber's Law and some examples of the theories that have tried to explain it. We revive the speculation that intracellular exo-and endocytotic processes are resource delivery-systems, analogous to the supercellular systems in multicellular organisms. Finally, we present data that cast doubt on the existence of a single scaling relationship between growth and body size in plants.

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Unitary exocytotic and endocytotic events in Zea mays L. coleoptile protoplasts

Cited by 33 publications

References 22 publications

A Rab-E GTPase Mutant Acts Downstream of the Rab-D Subclass in Biosynthetic Membrane Traffic to the Plasma Membrane in Tobacco Leaf Epidermis

A Rab-E GTPase Mutant Acts Downstream of the Rab-D Subclass in Biosynthetic Membrane Traffic to the Plasma Membrane in Tobacco Leaf Epidermis

Uptake of a Fluorescent Marker in Plant Cells Is Sensitive to Brefeldin A and Wortmannin

Kleiber's Law: How theFire of Lifeignited debate, fueled theory, and neglected plants as model organisms

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