ABSTRACT
Mitophagy is one of the important targets for the prevention and treatment of myocardial ischemia/reperfusion injury (MIRI). Moderate mitophagy can remove damaged mitochondria, inhibit excessive reactive oxygen species accumulation, and protect mitochondria from damage. However, excessive enhancement of mitophagy greatly reduces adenosine triphosphate production and energy supply for cell survival, and aggravates cell death. How dysfunctional mitochondria are selectively recognized and engulfed is related to the interaction of adaptors on the mitochondrial membrane, which mainly include phosphatase and tensin homolog deleted on chromosome ten (PTEN)-induced kinase 1/Parkin, hypoxia-inducible factor-1 α/Bcl-2 and adenovirus e1b19k Da interacting protein 3, FUN-14 domain containing protein 1 receptor-mediated mitophagy pathway and so on. In this review, the authors briefly summarize the main pathways currently studied on mitophagy and the relationship between mitophagy and MIRI, and incorporate and analyze research data on prevention and treatment of MIRI with Chinese medicine, thereby provide relevant theoretical basis and treatment ideas for clinical prevention of MIRI.
Subject(s)
Humans , Mitochondria/metabolism , Mitophagy/genetics , Myocardial Reperfusion Injury , Protein Kinases/metabolismABSTRACT
Objective To evaluate the expression of FUNDC1 and its clinical significance in non-small cell lung cancer. Methods We used TCGA database to analyze the difference of mitochondrial receptors (DRP1, BNIP3, FUNDC1, NIX, RHEB, LC3, OPA1 and MFN1) expression between normal and NSCLC tissues, as well as its effect on the prognosis of NSCLC patients. Immunohistochemistry was used to detect FUNDC1 expression. The correlations between FUNDC1 expression and clinicopathological characteristics, prognosis were evaluated by SPSS 22.0 statistical software. Results FUNDC1 expression was increased in NSCLC tissues, compared with normal tissues. FUNDC1 expression was related to the degree of differentiation and lymph node metastasis, but not to gender, age, pathological type, distant metastasis or TNM classification. The Cox regression analysis showed that FUNDC1 protein expression, lymph node metastasis, differentiation degree were independent prognostic factors of NSCLC. Increased FUNDC1 expression was related to decreased OS and PFS (P < 0.01). Conclusion The up-regulation of FUNDC1 expression can affect the prognosis of patients with NSCLC. It may be a new potential target for treating with NSCLC.
ABSTRACT
Mitophagy is an essential intracellular process that eliminates dysfunctional mitochondria and maintains cellular homeostasis. Mitophagy is regulated by the post-translational modification of mitophagy receptors. Fun14 domain-containing protein 1 (FUNDC1) was reported to be a new receptor for hypoxia-induced mitophagy in mammalian cells and interact with microtubule-associated protein light chain 3 beta (LC3B) through its LC3 interaction region (LIR). Moreover, the phosphorylation modification of FUNDC1 affects its binding affinity for LC3B and regulates selective mitophagy. However, the structural basis of this regulation mechanism remains unclear. Here, we present the crystal structure of LC3B in complex with a FUNDC1 LIR peptide phosphorylated at Ser17 (pS), demonstrating the key residues of LC3B for the specific recognition of the phosphorylated or dephosphorylated FUNDC1. Intriguingly, the side chain of LC3B Lys49 shifts remarkably and forms a hydrogen bond and electrostatic interaction with the phosphate group of FUNDC1 pS. Alternatively, phosphorylated Tyr18 (pY) and Ser13 (pS) in FUNDC1 significantly obstruct their interaction with the hydrophobic pocket and Arg10 of LC3B, respectively. Structural observations are further validated by mutation and isothermal titration calorimetry (ITC) assays. Therefore, our structural and biochemical results reveal a working model for the specific recognition of FUNDC1 by LC3B and imply that the reversible phosphorylation modification of mitophagy receptors may be a switch for selective mitophagy.