Investigating the role of PICK1 in regulating mitochondrial fusion/fission

• Main Authors: Shu-Han Hsu, 許書涵
• Other Authors: Wey-Jinq Lin
• Format: Others
• Language: zh-TW
• Published: 2015
• Online Access: http://ndltd.ncl.edu.tw/handle/77689389346599177975

碩士 === 國立陽明大學 === 生物藥學研究所 === 103 === PICK1 (protein that interacts with C kinase 1) is a scaffold protein. Our previous studies have shown that PICK1 proteins are localized in mitochondrial in fibroblasts and several cancer cell lines. PICK1 stabilizes mitochondrial membrane potential by recruiting protein kinase Cα leading to an increased resistance to chemotherapeutical agents. Notably, knockdown of PICK1 in NIH3T3 fibroblasts led to an increase in mitochondrial fragmentation, a decrease in ATP production, a reduction in oxygen consumption, and a remarkable dependence on glucose for survival, suggesting that PICK1 plays an important role in maintaining mitochondrial functions. Mitochondria are dynamic organelles constantly undergoing fission and fusion to maintain a steady network which is tightly associated with cellular functions. Ectopic expression of either MFN2 or OPA1 proteins, two known key players in mitochondrial fusion, couldn’t restore mitochondrial network in PICK1-deficient cells. Knockdown of MFN2 caused sever mitochondrial fragmentation, however ectopic expression of PICK1 could not restore either. There are several forms of OPA1 proteins in cells. A proper combination of the short form (S-form) and long form (L-form) OPA1 is essential for its functions. My study showed that in the presence of mitochondrial electron chain uncoupler CCCP, the L-form OPA1 was rapidly processed and converted to S-form in the PICK1-knockdown (KD) context. This may contribute to the increased mitochondrial fragmentation. My results showed that PICK1-deficiency caused a remarkable decrease in the activity of mitochondrial electron transport chain by using a real-time measurement. These results support that PICK1-defifiency caused the impairment of mitochondrial electron transport chain which may lead to an increased sensitivity to cellular stresses.