Reep2, a member of the receptor expression-enhancing protein (ER) [1]. The REEP family is involved in ER morphogenesis, microtubule cytoskeleton regulation, and the trafficking and expression of G protein-coupled receptors (GPCRs), playing crucial roles in numerous physiological and pathological processes [1].

Mutations in Reep2 have been identified as a cause of "pure" hereditary spastic paraplegias (HSPs), SPG72, with both autosomal dominant and autosomal recessive inheritance [2]. In a Nepalese family, a heterozygous Reep2 missense mutation (c.119T>G, p.Met40Arg) led to early-onset pure-type HSP [2]. Another study reported a patient with a de novo missense mutation (c.119T > G, p.Met40Arg) in Reep2 resulting in pure hereditary spastic paraplegia [5]. Additionally, three mutations in Reep2 were found in two HSP families, with one missense variant in an autosomal-dominant family having a dominant-negative effect on normal membrane binding, and a missense substitution in a recessive family decreasing the protein's membrane affinity [7]. In nasopharyngeal carcinoma, Reep2 was upregulated, and its high expression was associated with poor survival [3]. Reep2 also enhances sweet receptor function by recruiting it to lipid rafts in taste cells [4], and acts as a negative regulator of adipogenic differentiation of bone marrow-derived mesenchymal stem cells [6].

In conclusion, Reep2 is essential for maintaining normal cellular functions related to ER-associated processes, taste receptor function, and adipogenic differentiation. Its malfunction due to mutations is closely associated with the development of hereditary spastic paraplegias and may contribute to the progression of nasopharyngeal carcinoma. Research on Reep2 knockout or conditional knockout models could potentially further clarify its role in these disease conditions, providing insights for better understanding of the pathophysiology and potential therapeutic strategies.

References:

1. Fan, Sisi, Liu, Huimei, Li, Lanfang. 2022. The REEP family of proteins: Molecular targets and role in pathophysiology. In Pharmacological research, 185, 106477. doi:10.1016/j.phrs.2022.106477. https://pubmed.ncbi.nlm.nih.gov/36191880/

2. Nan, Haitian, Takaki, Ryusuke, Hata, Takanori, Koh, Kishin, Takiyama, Yoshihisa. 2021. A Nepalese family with an REEP2 mutation: clinical and genetic study. In Journal of human genetics, 66, 749-752. doi:10.1038/s10038-020-00882-x. https://pubmed.ncbi.nlm.nih.gov/33526816/

3. Wang, Yong, Peng, Lisha, Wang, Feng. 2024. M6A-mediated molecular patterns and tumor microenvironment infiltration characterization in nasopharyngeal carcinoma. In Cancer biology & therapy, 25, 2333590. doi:10.1080/15384047.2024.2333590. https://pubmed.ncbi.nlm.nih.gov/38532632/

4. Ilegems, Erwin, Iwatsuki, Ken, Kokrashvili, Zaza, Ninomiya, Yuzo, Margolskee, Robert F. . REEP2 enhances sweet receptor function by recruitment to lipid rafts. In The Journal of neuroscience : the official journal of the Society for Neuroscience, 30, 13774-83. doi:10.1523/JNEUROSCI.0091-10.2010. https://pubmed.ncbi.nlm.nih.gov/20943918/

5. Roda, Ricardo H, Schindler, Alice B, Blackstone, Craig. 2017. De novo REEP2 missense mutation in pure hereditary spastic paraplegia. In Annals of clinical and translational neurology, 4, 347-350. doi:10.1002/acn3.404. https://pubmed.ncbi.nlm.nih.gov/28491902/

6. Zhang, Xianning, Liu, Lulu, Liu, Xin, Zhang, Hao, Chen, Mingtai. 2023. Chidamide suppresses adipogenic differentiation of bone marrow derived mesenchymal stem cells via increasing REEP2 expression. In iScience, 26, 106221. doi:10.1016/j.isci.2023.106221. https://pubmed.ncbi.nlm.nih.gov/36879811/

7. Esteves, Typhaine, Durr, Alexandra, Mundwiller, Emeline, Stevanin, Giovanni, Darios, Frédéric. 2014. Loss of association of REEP2 with membranes leads to hereditary spastic paraplegia. In American journal of human genetics, 94, 268-77. doi:10.1016/j.ajhg.2013.12.005. https://pubmed.ncbi.nlm.nih.gov/24388663/