Regulation of Mitochondrial Genome Inheritance by Autophagy and Ubiquitin-Proteasome System: Implications for Health, Fitness, and Fertility
Figure 2
Immunofluorescence localization of GABARAP, p62/SQSTM1, and VCP in porcine zygotes. (a) Autophagy receptor/ubiquitin-like protein GABARAP accumulates around male pronucleus and sperm mitochondria of an embryo treated with proteasomal inhibitor MG132 (100 uM) at 30 hr after insemination. Inhibition of proteasomal proteolysis is known to induce compensatory activation of autophagic pathway. (b) Ubiquitin-binding protein p62/SQSTM1 is detected in the mitochondria region of spermatozoa in embryo cultured for 30 hr after IVF. SQSTM1 is an ubiquitin-receptor that links UPS to autophagic pathway. (c) Protein dislocase p97/VCP is present in the mitochondrial sheath of spermatozoa in a porcine zygote cultured for 30 hr after IVF. Dislocase VCP recognizes and extracts ubiquitinated mitochondrial membrane proteins, presenting them to 26S proteasome for degradation.
