Dynamic localization of a yeast development–specific PP1 complex during prospore membrane formation is dependent on multiple localization signals and complex formation

During the developmental process of sporulation in Saccharomyces cerevisiae, membrane structures called prospore membranes are formed de novo, expand, extend, acquire a round shape, and finally become plasma membranes of the spores. GIP1 encodes a regulatory/targeting subunit of protein phosphatase type 1 that is required for sporulation. Gip1 recruits the catalytic subunit Glc7 to septin structures that form along the prospore membrane; however, the molecular basis of its localization and function is not fully understood. Here we show that Gip1 changes its localization dynamically and is required for prospore membrane extension. Gip1 first associates with the spindle pole body as the prospore membrane forms, moves onto the prospore membrane and then to the septins as the membrane extends, distributes around the prospore membrane after closure, and finally translocates into the nucleus in the maturing spore. Deletion and mutation analyses reveal distinct sequences in Gip1 that are required for different localizations and for association with Glc7. Binding to Glc7 is also required for proper localization. Strikingly, localization to the prospore membrane, but not association with septins, is important for Gip1 function. Further, our genetic analysis suggests that a Gip1–Glc7 phosphatase complex regulates prospore membrane extension in parallel to the previously reported Vps13, Spo71, Spo73 pathway

A fixation guide for the accurate insertion of fibular segments in mandibular reconstruction

Background: Computer-aided design and computer-assisted manufacturing (CAD/CAM) of cutting guides are now being used in mandibular reconstruction with fibular bone flaps. Improvements in guide design and accuracy are needed to increase the benefits to patients. Cutting guides have become popular, but fixation guides are rarely considered. Materials and methods: The aim of this study was to determine whether using a fixation guide would contribute to better accuracy in mandibular reconstruction. Mandibular segmental osteotomies and fibular reconstructions were performed using model surgery. Models were divided into two groups: without or with a fixation guide (n = 13 for each group). After reconstruction, the distances between reference points such as the condylion laterale (Cl), gonion, and mental tubercle (T) were measured and compared with those of the preoperative virtual plan. Deviations in final positions between the two groups were analyzed. Results: The mean deviations were 2.61 mm (range 0.05–7.65 mm) and 2.05 mm (range 0.07–8.52 mm) in the groups without and with a fixation guide, respectively. The overall results were significantly better when a fixation guide was used (p = 0.03). Distances including the Cl reference points such as ClCl (p = 0.02) and Cl–T (p = 0.001) were particularly improved. Conclusions: Using a fixation guide together with a cutting guide makes mandibular reconstruction more accurate, particularly for positioning the Cl reference points. Therefore, when a CAD/CAM-produced cutting guide is used in preparation for surgery, it is recommended to use a fixation guide as well for more accuracy