FCHO2, a member of the FCFBS superfamily, contains an F-BAR domain. It plays crucial roles in multiple cellular processes such as membrane trafficking, particularly in clathrin-mediated endocytosis (CME) [3,2,5,4]. It is also involved in maintaining the Golgi architecture, which is essential for proper secretory pathway function [1]. Genetic models like gene knockout (KO) or conditional knockout (CKO) mouse models can be valuable for studying its functions.

In terms of its functions, siRNA-mediated reduction of FCHO2 leads to Golgi fragmentation, affecting the uniform distribution of Golgi enzymes for carbohydrate modification and preventing the exchange of resident membrane proteins between Golgi ministacks [1]. In CME, FCHO2 assembles at the rim of clathrin-coated endocytic pits (CCPs), controlling CCP growth and lifetime by coupling early endocytic intermediate invagination to clathrin lattice assembly [4]. FCHO2 knockdown reduces transferrin endocytosis, suggesting its role in regulating CME through membrane and Eps15 interactions [5]. Also, the effector Cig57 of Coxiella burnetii hijacks FCHO2-mediated vesicular trafficking, and siRNA gene silencing or knockout of FCHO2 inhibits the growth and vacuole biogenesis of this pathogen [6].

In conclusion, FCHO2 is essential for maintaining Golgi architecture and regulating clathrin-mediated endocytosis. The use of KO/CKO mouse models (although not directly described in the given references but conceptually relevant) could further clarify its role in these processes. Its disruption impacts the intracellular replication of pathogens like Coxiella burnetii, highlighting its significance in host-pathogen interactions. Understanding FCHO2 provides insights into normal cellular functions and potential disease mechanisms related to membrane trafficking and pathogen-host relationships.

References:

1. Bagley, Dustin C, Morham, Scott G, Kaplan, Jerry, Ward, Diane M. 2023. Mon1a and FCHO2 are required for maintenance of Golgi architecture. In bioRxiv : the preprint server for biology, , . doi:10.1101/2023.07.06.547837. https://pubmed.ncbi.nlm.nih.gov/37461455/

2. El Alaoui, Fatima, Casuso, Ignacio, Sanchez-Fuentes, David, Carretero-Genevrier, Adrian, Picas, Laura. 2022. Structural organization and dynamics of FCHo2 docking on membranes. In eLife, 11, . doi:10.7554/eLife.73156. https://pubmed.ncbi.nlm.nih.gov/35044298/

3. Katoh, Masuko, Katoh, Masaru. . Identification and characterization of human FCHO2 and mouse Fcho2 genes in silico. In International journal of molecular medicine, 14, 327-31. doi:. https://pubmed.ncbi.nlm.nih.gov/15254787/

4. Lehmann, Martin, Lukonin, Ilya, Noé, Frank, Loerke, Dinah, Haucke, Volker. 2019. Nanoscale coupling of endocytic pit growth and stability. In Science advances, 5, eaax5775. doi:10.1126/sciadv.aax5775. https://pubmed.ncbi.nlm.nih.gov/31807703/

5. Uezu, Akiyoshi, Umeda, Kazuaki, Tsujita, Kazuya, Takenawa, Tadaomi, Nakanishi, Hiroyuki. 2011. Characterization of the EFC/F-BAR domain protein, FCHO2. In Genes to cells : devoted to molecular & cellular mechanisms, 16, 868-78. doi:10.1111/j.1365-2443.2011.01536.x. https://pubmed.ncbi.nlm.nih.gov/21762413/

6. Latomanski, Eleanor A, Newton, Patrice, Khoo, Chen Ai, Newton, Hayley J. 2016. The Effector Cig57 Hijacks FCHO-Mediated Vesicular Trafficking to Facilitate Intracellular Replication of Coxiella burnetii. In PLoS pathogens, 12, e1006101. doi:10.1371/journal.ppat.1006101. https://pubmed.ncbi.nlm.nih.gov/28002452/