Cell cycle control by Ca2+ in Saccharomyces cerevisiae.

Abstract. Metal ion requirements for the proliferation of Saccharomyces cerevisiae were investigated. We used bis- ( o-aminophenoxy )-ethane-N,N,N ',N '-tetraacetic acid (BAPTA), a relatively acid tolerant chelator, to reduce the free metal ion concentrations in culture media. Chelatable metal ions were added back individually and in combination. In addition to a requirement for ~10 pM external free Zn 2+ we found an interchangeable requirement for either 66 nM free Ca 2÷ or only 130 pM free Mn 2+. Cells depleted of Mn 2+ and Ca 2÷ arrested as viable cells with 2 N nuclei and tended to have very small minibuds. In the absence of added Mn 2÷, robust growth required --~60 IxM total internal Ca 2÷. In the presence of added Mn 2+, robust growth continued even when internal Ca 2+ was <3% this level. Chelatorfree experiments showed that MnCI2 strongly and CaC12 weakly restored high-temperature growth of cdcl ts strains which similarly arrest as viable cells with 2 N nuclear contents and small buds. Its much greater effectiveness compared with Ca 2+ suggests that Mn 2+ is likely to be a physiologic mediator of bud and nuclear development in yeast. This stands in marked contrast to a claim that Ca 2+ is uniquely required for cell-cycle progression in yeast. We discuss the possibility that Mn 2+ may function as an intracellular signal transducer and how this possibility relates to previous claims of Ca 2+'s roles in yeast metabolism. (Goscin and Fridovich, 1972;Bragg, 1974;Busse, 1984;Baum et al., 1986;Eisen et al., 1988;Anraku et al., 1991), a rigorous survey of nutritional metal ion requirements of yeast has never been undertaken. The recipe of yeast synthetic medium (SD) 1 in common use today was formulated over 40 years ago as a general medium for a diverse array of fungi (Wickersham, 1951). The ingredients of this medium include, besides those of Mg 2÷ and monovalents, salts of Ca 2+, Mn 2+, Cu 2+, Zn 2+, and Fe 3+. These five metal ions ranked essential, because they were dietary requirements of mammals and were present in trace amounts in yeast ash. Withholding from the medium the supplements of all five of these essential metal ions, including Ca 2+, does not stop growth, though. Such a culture presumably thrives on residual metal ions contaminating the medium. Even the addition of as much as 10 mM of the metal-ion chelator EGTA to synthetic medium containing only contaminat- ESPITE biochemical and genetic evidence for metal ion use in Saccharomyces cerevisiae

contrasting

confidence: 99%

“…Like other investigators (Kovac, 1985;Iida et al, 1990a), we failed to block yeast multiplication by adding EGTA alone to the standard rich medium YEPD (~pH 5.8). We found that EGTA did block growth when added to YEPD buffered at pH 7.0.…”

Section: Bapta Arrests Growth In Rich Mediamentioning

confidence: 66%

Manganese effectively supports yeast cell-cycle progression in place of calcium.

Loukin

Kung

1995

“…In mammalian cells, various stimuli are known to induce the release of Ca 2 ϩ from the endoplasmic or sarcoplasmic reticulum, the primary Ca 2 ϩ stores. In yeast, the Ca 2 ϩ concentration in the cytosol ([Ca 2 ϩ ] cyt )* has been shown to increase in response to the mating pheromone ␣ factor (Iida et al, 1990), hypotonic shock (Batiza et al, 1996, Beeler et al, 1997, and addition of glucose to starving cells (Nakajima-Shimada et al, 1991). However, none of these increases in [Ca 2 ϩ ] cyt has been shown to depend on internal Ca 2 ϩ release, as opposed to influx from the external media.…”

Section: Introductionmentioning

confidence: 99%

Internal Ca2+ release in yeast is triggered by hypertonic shock and mediated by a TRP channel homologue

Denis

Cyert

2002

281

265

Calcium ions, present inside all eukaryotic cells, are important second messengers in the transduction of biological signals. In mammalian cells, the release of Ca2+ from intracellular compartments is required for signaling and involves the regulated opening of ryanodine and inositol-1,4,5-trisphosphate (IP3) receptors. However, in budding yeast, no signaling pathway has been shown to involve Ca2+ release from internal stores, and no homologues of ryanodine or IP3 receptors exist in the genome. Here we show that hyperosmotic shock provokes a transient increase in cytosolic Ca2+ in vivo. Vacuolar Ca2+, which is the major intracellular Ca2+ store in yeast, is required for this response, whereas extracellular Ca2+ is not. We aimed to identify the channel responsible for this regulated vacuolar Ca2+ release. Here we report that Yvc1p, a vacuolar membrane protein with homology to transient receptor potential (TRP) channels, mediates the hyperosmolarity induced Ca2+ release. After this release, low cytosolic Ca2+ is restored and vacuolar Ca2+ is replenished through the activity of Vcx1p, a Ca2+/H+ exchanger. These studies reveal a novel mechanism of internal Ca2+ release and establish a new function for TRP channels.

“…: 44 191 222 5264. Fax: 44 191 222 5296. as EGTA and BAPTA blocks both entry into, and exit from, mitosis (Steinhardt and Alderton, 1988;Twigg et al, 1988;Whitaker and Patel, 1990;Patel et al, 1989Patel et al, , 1990Ohsumi and Anraku, 1983;Iida et al, 1990;Lindsay et al, 1995). Entry into mitosis can also be induced prematurely by microinjection of calcium during a defined period before mitosis entry (Steinhardt and Alderton, 1988;Twigg et al, 1988;Patel et al, 1989Patel et al, , 1990Kao et al, 1990).…”

mentioning

confidence: 99%

Local perinuclear calcium signals associated with mitosis-entry in early sea urchin embryos.

Wilding

Wright

Patel

et al. 1996

Abstract. Using calcium-sensitive dyes together with their dextran conjugates and confocal microscopy, we have looked for evidence of localized calcium signaling in the region of the nucleus before entry into mitosis, using the sea urchin egg first mitotic cell cycle as a model. Global calcium transients that appear to originate from the nuclear area are often observed just before nuclear envelope breakdown (NEB). In the absence of global increases in calcium, confocal microscopy using Calcium Green-1 dextran indicator dye revealed localized calcium transients in the perinuclear region.We have also used a photoinactivatable calcium chelator, nitrophenyl EGTA (NP-EGTA), to test whether the chelator-induced block of mitosis entry can be reversed after inactivation of the chelator. Cells arrested before NEB by injection of NP-EGTA resume the cell cycle after flash photolysis of the chelator. Photolysis of chelator triggers calcium release. Treatment with caffeine to enhance calcium-induced calcium release increases the amplitude of NEB-associated calcium transients. These results indicate that calcium increases local to the nucleus are required to trigger entry into mitosis. Local calcium transients arise in the perinuclear region and can spread from this region into the cytoplasm. Thus, cell cycle calcium signals are generated by the perinuclear mitotic machinery in early sea urchin embryos. INTRACELLULAR calcium is now known to perform a wide variety of functions as a second messenger. It is implicated in the control of exocytosis, protein synthesis, locomotion, and synaptic transmission (for reviews see Campbell, 1983;Berridge, 1993; Brostrom and Brostrom, 1990;Rasmussen and Rasmussen, 1990). It is increasingly clear that calcium signals can originate in specific cytoplasmic domains (Lechleiter et al., 1991;Rizzuto et al., 1993;Meyer et al., 1995;Petersen, 1995;Kasai, 1995). A body of evidence also points to a role for calcium ions as one of the mechanisms enabling passage through cell cycle control points (for reviews see Whitaker and Patel, 1990;Steinhardt, 1990;Lu and Means, 1993;Whitaker, 1995).The evidence for a role of calcium ions during mitosis comes from observations that embrace many different aspects of cell cycle physiology. For example, many components of the intracellular calcium signaling system localize to the area of the nucleus just before mitosis entry and to the mitotic apparatus during mitosis (Silver et al., 1980; Keihart, 1981;Petzelt, 1979Petzelt, , 1984Petzelt and Hafner, 1986;Wolniak et al., 1981; Paweletz and Firze, 1981;Hepler, 1980; Wolniak, 1983, 1984 as EGTA and BAPTA blocks both entry into, and exit from, mitosis (Steinhardt and Alderton, 1988;Twigg et al., 1988;Whitaker and Patel, 1990;Patel et al., 1989Patel et al., , 1990Ohsumi and Anraku, 1983;Iida et al., 1990; Lindsay et al., 1995). Entry into mitosis can also be induced prematurely by microinjection of calcium during a defined period before mitosis entry (Steinhardt and Alderton, 1988;Twigg et al., 1988;Patel et al., 1989...