Cell cycle‐dependent protein secretion by Saccharomyces cerevisiae

Abstract

Synchronized Saccharomyces cerevisiae cell populations were used to examine secretion rates of a heterologous protein as a function of cell cycle position. The synchronization procedure had a profound effect on the type and quality of data obtained. When cell synchrony was induced by cell cycle-arresting drugs, a significant physiological perturbation of cells was observed that obscured representative secretion data. In contrast, synchronization with centrifugal elutriation resulted in synchronized first-generation daughter cells with undetectable perturbation of the physiological state. The synchronized cells did not secrete significant amounts of protein until they reached cell division, suggesting that the secretion process in these cells is strongly cell cycle dependent. However, the maximum secretion rate of the synchronized culture (7-14 molecules/cell/second) was significantly lower than that of an asynchronous culture (29-51 molecules/cell/second). This result indicates that young daughter cells isolated in the synchronization process exhibit different protein secretion behavior than older mother cells that are absent in the synchronized cell population but present in the asynchronous culture.

Investigating the effect of carbon source on rabies virus glycoprotein production inPichia pastorisby a transcriptomic approach

“…On the other hand, Buchetics et al (2011) reported that P. pastoris recombinants clones exhibiting a high secretion level are mostly in the G2 and M phases of cell cycle. The relation between cell cycle phase and protein production has been described not only in yeasts (Frykman & Srienc, 2001) but also in mammalian cells (Charlet, Kromenaker, & Srienc, 1995). The eukaryotic cell cycle has been examined comprehensively in the model organism S. cerevisiae reviewed in Cid et al (2002).…”

Disentangling signaling gradients generated by equivalent sources

“…While maintaining maximal absorption rate of 10 4 pheromone molecules per second appears well within the expected biological regime, it is important to note that the estimated pheromone secretion rates required for efficient activation of the mating response (η ∼ 6,000 mol/s) appears exceedingly high. Although direct measurements of α-factor secretion rates are not available, corresponding estimates for protein secretion rate are on the order of magnitude of 10 molecules/second [23,24]. Moreover, since α-factor mRNA is present at only ∼10-50 copies per cell [25], it is unlikely that more than ∼100 mature α-factor molecules will be produced per second, considering a translation initiation rate of about ∼0.1-1 s −1 (rate limiting step), even when taking into account the fact that there are six repetitions of the peptide within the genome [26].…”

A Population Balance Model Describing the Cell Cycle Dynamics of Myeloma Cell Cultivation

“…For example, maximum secretion rate of antibody had been found in the G2M phase of murine hybridoma cells (12). Experimental data derived from Saccharomyces cereVisiae had also shown that a heterologous protein of interest was mainly secreted during the late G2 and M phases (13,14). Thus, the accurate mathematical description of such processes and the control of the cell cycle specific products can only be achieved by using multi-staged models (5).…”