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- FUNCTIONAL ANALYSIS OF UBIQUITIN-LIKE PROTEIN 4A
- Zhao, Yu
- 2015, 2015-12
Ubiquitin-like protein 4A (Ubl4A) was identified as a housekeeping gene at X chromosome. It involves in the guided entry of tail-anchored (GET...
Show moreUbiquitin-like protein 4A (Ubl4A) was identified as a housekeeping gene at X chromosome. It involves in the guided entry of tail-anchored (GET) protein pathway in which tail-anchored (TA) proteins are transported to endoplasmic reticulum (ER). However, Ubl4A also involves other functions not related to GET pathway, such as tumor suppression and DNA damage-mediated apoptosis. Up to date, the function of Ubl4A in mammals is still largely unknown. We found that either overexpression or knockdown of Ubl4A promoted cell death in cell culture system. Using an in vivo genetic knockout system, we found that Ubl4A knockout mice displayed a high neonatal mortality and had a defect in glycogen synthesis, which is mainly controlled by a key protein kinase Akt. Loss of Ubl4A resulted in the impairment of insulin-induced Akt translocation to the plasma membrane, an essential step for Akt activation. We demonstrated that Ubl4A directly interacted with actin-related protein 2/3 (Arp2/3) complex, further accelerated Arp2/3 complex-dependent actin branching, thereby bringing Akt to proximity into the plasma membrane for activation. Furthermore, we showed that Ubl4A-mediated actin branching also played important roles in other cellular activities, such as formations oflamellipodia and filopodia, macrophage phagocytosis, wound healing, and neutrophil chemotaxis. These findings provide us a new insight into understanding the roles of Ubl4A in cellular function and a molecular basis for treatment of related human diseases.
Ph.D. in Biology, December 2015
- SAFETY AND MOBILITY IMPACTS ASSESSMENT OF THE CHICAGO BIKE LANE PROGRAM
- Zhao, Yu
In recent years, bike as a travel mode is getting increasingly popular among large cities in the U.S. These cities also found promoting bike...
Show moreIn recent years, bike as a travel mode is getting increasingly popular among large cities in the U.S. These cities also found promoting bike mode can potentially mitigate traffic congestion issues, reduce carbon emission and improve the quality of life for residents. Therefore, many cities-initiated bike-related programs promote the bike mode from all aspects, such as establishing a shared bike system and developing bike-related facilities. Specifically, bike lane installation is widely seen in large cities as a pivot component of bike promotion programs. Due to the installation of bike lanes on the existing network, vehicles’ safety and mobility performance may be affected due to the variation of facilities. This study attempts to propose a methodology to quantify the safety and mobility impacts on vehicles brought by bike lane installation. The proposed method accounts for safety impact by using predicted crashes in conjunction with field observed crash data for empirical Bayes (EB) before-after comparison group analysis. The mobility impact is captured by comparing the segment average travel time before and after the bike lane installation. Further, vehicle volume information is involved in the consumer surplus computation to quantify the variation in vehicle safety, and mobility performance resulting from the bike lane installation. A case study is conducted using a real data set from the city of Chicago bike lane program. The results reveal that the safety and mobility impacts vary mainly depending on the type of bike lane installed and location.