Golgi ReAssembly Stacking Proteins - Essay Example

General protein secretion was also unencumbered. Furthermore, the absence of GRASPs in plants has not prevented them from acquiring proper stacking of the cisterna membranes. It is in the confusion regarding the true physiological function of the GRASPs that Kutzen and his colleagues conducted their study. They sought an explanation of why GRASPs exist by determining and establishing their role in cellular development. The authors present a new perspective on the physiological role of GRASPs.

They contend that these proteins are not needed for conventional protein secretion, growth (i.e. stacking), and viability of vegetative cells. Their importance lies in making sure that Acebo, a protein that initiates spore differentiation, is secreted. Since Acebo lacks a signal sequence for its transport to the site where terminal differentiation occurs, GRASPs present an unconventional mechanism that facilitates the secretion and transportation of Acebo. Since spore differentiation ultimately results in fruiting bodies containing mature spores, GRASPs can be thought of as necessary for the reproductive mechanism of the cell and not the stacking of the membranes.3.0 Major FindingsThru the use of cells of Dictyostelium, a type of mold, the authors found that GRASPs are not necessary for ensuring cell growth and viability.

This was the result of comparing the Golgi structure of cells containing GRASP and those without thru the use of immunofluorescence microscopy. The structure, even the stacking of the Golgi membranes, was similar for both cases. In proving their hypothesis, the authors studied the prespore cell type of the mold. With molds that have GRASPs as the control and those without as the experimental variable, they were able to determine that the viability of the mature spores in the control was 100% as compared to the 25% of those negative for GRASPs.

Digging deeper, the authors were able to determine that the decrease in viability was the result of the insignificant production of SDF-2, a major peptide factor necessary for proper spore formation. According to Anjard and Loomis (2005), SDF-2 is generated in the cleaving of Acebo. The cleaving of the protein Acebo initiates a loopback process that ultimately results in a successful sporulation event. The question now that faced the authors was to determine how GRASPs affected the production of Acebo.

After having conducted Western blot analysis on molds that did not have GRASPs, they found that Acebo was still as abundant as that in normal conditions.