Efcab2, an EF-hand calcium-binding domain-containing gene, encodes a protein that is involved in calcium-binding functions. Calcium-binding proteins are crucial for regulating ion metabolism and signaling pathways, especially in sperm maturation [1]. Efcab2 has been implicated in various biological processes and disease conditions.

In mouse studies, Efcab2 was found to be a novel calcium-binding protein specifically expressed in testis and sperm. It contains two EF-hand motifs and is conserved among eukaryotes. Its mRNA was detected only in the testis, and the protein was localized in spermatogenic cells from primary spermatocytes to elongate spermatids, as well as in the principal piece of cauda epididymal sperm flagellum. Functional analysis showed its ability to bind Ca2+, suggesting a role in controlling sperm flagellar movement [1].

In Wilms' tumor, Efcab2 was identified as one of the key carcinogenic genes, with its expression positively correlated with poor patient survival [2]. In non-small cell lung cancer patients, genetic variants in Efcab2 were significantly associated with gemcitabine/carboplatin-induced leukopenia [3]. In temporal lobe epilepsy, circ-EFCAB2 was intensely up-regulated, and it may bind to miR-485-5p to increase the expression of the ion channel CLCN6, potentially reflecting the pathogenesis of the disease [4].

In conclusion, Efcab2 is an important gene with diverse functions. Its role in calcium-binding in sperm and its association with diseases such as Wilms' tumor, non-small cell lung cancer-related drug-induced leukopenia, and temporal lobe epilepsy have been revealed through various studies. These findings enhance our understanding of the biological processes and disease mechanisms associated with Efcab2.