Exoc7, also known as Exo70, is a key component of the exocyst complex. The exocyst complex is involved in tethering secretory vesicles to the plasma membrane before SNARE-mediated membrane fusion, playing a crucial role in processes like exocytosis, cell adhesion, migration, and invasion [5,6]. It is associated with pathways related to intracellular trafficking and membrane-trafficking, and its proper function is essential for normal physiological processes [1,2]. Genetic models, such as knockout mice, have been valuable in studying its functions.

In an inducible adipocyte genome editing system, Exoc7 gene deletion in adipocytes inhibited insulin-stimulated GLUT4 exocytosis, indicating the exocyst's critical role in this process [2]. In male germ cell-specific conditional knockout (cKO) mice, depletion of Exoc7 led to severe spermatogenesis defects, suggesting the importance of the exocyst complex in spermatogenesis [4]. In zebrafish, absence of exoc7 caused microcephaly, highlighting its role in normal cortical development [3].

In conclusion, Exoc7 is essential for processes like insulin-regulated GLUT4 exocytosis, spermatogenesis, and cerebral cortical development. The Exoc7 KO/CKO mouse models have significantly contributed to understanding its role in adipocyte function, spermatogenesis, and provided insights into potential mechanisms underlying brain development disorders [2,3,4].

References:

1. Georgilis, Athena, Klotz, Sabrina, Hanley, Christopher J, Zender, Lars, Gil, Jesús. . PTBP1-Mediated Alternative Splicing Regulates the Inflammatory Secretome and the Pro-tumorigenic Effects of Senescent Cells. In Cancer cell, 34, 85-102.e9. doi:10.1016/j.ccell.2018.06.007. https://pubmed.ncbi.nlm.nih.gov/29990503/

2. Wang, Shifeng, Crisman, Lauren, Miller, Jessica, Yu, Haijia, Shen, Jingshi. 2019. Inducible Exoc7/Exo70 knockout reveals a critical role of the exocyst in insulin-regulated GLUT4 exocytosis. In The Journal of biological chemistry, 294, 19988-19996. doi:10.1074/jbc.RA119.010821. https://pubmed.ncbi.nlm.nih.gov/31740584/

3. Coulter, Michael E, Musaev, Damir, DeGennaro, Ellen M, Gleeson, Joseph G, Walsh, Christopher A. 2020. Regulation of human cerebral cortical development by EXOC7 and EXOC8, components of the exocyst complex, and roles in neural progenitor cell proliferation and survival. In Genetics in medicine : official journal of the American College of Medical Genetics, 22, 1040-1050. doi:10.1038/s41436-020-0758-9. https://pubmed.ncbi.nlm.nih.gov/32103185/

4. Mikami, Natsuki, Nguyen, Chi Lieu Kim, Osawa, Yuki, Takahashi, Satoru, Mizuno, Seiya. 2024. Deletion of Exoc7, but not Exoc3, in male germ cells causes severe spermatogenesis failure with spermatocyte aggregation in mice. In Experimental animals, 73, 286-292. doi:10.1538/expanim.23-0171. https://pubmed.ncbi.nlm.nih.gov/38325858/

5. Wu, Bin, Guo, Wei. 2015. The Exocyst at a Glance. In Journal of cell science, 128, 2957-64. doi:10.1242/jcs.156398. https://pubmed.ncbi.nlm.nih.gov/26240175/

6. Zhu, Yueyao, Wu, Bin, Guo, Wei. 2017. The role of Exo70 in exocytosis and beyond. In Small GTPases, 10, 331-335. doi:10.1080/21541248.2017.1328998. https://pubmed.ncbi.nlm.nih.gov/28489961/