Unveiling the Physical and Functional Niches of FAM26F by Analyzing Its Subcellular Localization and Novel Interacting Partners

Abstract

The knowledge of a protein’s subcellular localization and interacting partners are crucial for elucidating its cellular function and associated regulatory networks. Although FAM26F (family with sequence similarity 26, member F) has been recognized as a vital player in various infections, stimulation studies, cancer, and immune pathogenesis, the precise location and function of FAM26F are not well understood. The current study is the first to focus on functional characterization of FAM26F by analyzing its subcellular localization and identifying its novel interacting partners using advanced proteome approaches. The immunofluorescence and confocal microscopy results revealed FAM26F to be largely localized within the Golgi apparatus of the cell. However, its minor presence in endoplasmic reticulum (ER) pointed toward the probable retrograde transfer of FAM26F from Golgi to ER during adverse conditions. Moreover, co-immunoprecipitation and MS/MS results demonstrated a total of 85 proteins, 44 of which significantly copurified with FAM26F. Interestingly, out of these 44 MS/MS identified proteins, almost 52% were involved in innate immunity, 38.6% in neutrophil degranulation, and remaining 10% were either involved in phosphorylation, degradation, or regulation of apoptosis. Further characterization through Ingenuity Pathway Analysis showed that majority of these proteins was involved in maintaining calcium homeostasis of cell. Consequently, the validation of selected proteins uncovered the key interaction of FAM26F with Thioredoxin, which essentially paved the way for depicting its mechanism of action under stress or disease conditions. It is proposed that activation and inhibition of the cellular immune response is essentially dependent on whether FAM26F or Thioredoxin considerably interact with CD30R.

Effect of oxidative stress and calcium deregulation on FAM26F (CALHM6) expression during hepatitis B virus infection

“…FAM26F, also termed as Calcium homeostasis modulator protein 6 (CALHM6), has recently been recognized as a potent innate immunity modulator, owing to its calcium homeostasis modulator domain [ 19 ]. Previously, we have demonstrated that FAM26F is functionally related to calcium-binding proteins, specifically to Thioredoxin, and it was proposed that the FAM26F expression is regulated by cytosolic calcium disturbances [ 20 ]. Likewise, the HBV expression has also been shown to be linked with disturbance in calcium homeostasis and up-regulation of ROS levels [ 2 , 3 ].…”

“…Interestingly, FAM26F possesses a conserved Calcium homeostasis modulator (Ca_hom-mod) domain, hence also named as Calcium homeostasis modulator protein 6 (CALHM6) [ 19 ]. Recently, FAM26F was found to be functionally related to calcium-binding proteins, and it was proposed that the FAM26F expression is regulated by cytosolic calcium disturbances [ 20 ]. Moreover, FAM26F was identified as one of the top classifiers among 371 differentially expressed genes that were functionally linked with oxidative stress and inflammation [ 21 ].…”

Comprehensive bioinformatics-based annotation and functional characterization of bovine chymosin protein revealed novel biological insights

“…Bioinformatics can be used to forecast the structural and functional characteristics of proteins. Numerous studies explored bioinformatics approaches to understand protein sequence conservation, evolutionary relationships, functional domains, active sites, physiochemical properties, and so on ( Lagunas-Rangel, 2023 , Malik et al, 2020 , Narang et al, 2021 ). After examining the relevant literature, we could not find adequate information concerning these crucial aspects of bovine chymosin.…”