Structural and functional analysis of aquaporins in Bombus terrestris

• Published in: International journal of biological macromolecules 2024-08, Vol.275 (Pt 2), p.133692, Article 133692
• Main Authors: Ma, Xiaomei, Chang, Xinya, Liu, Geyuan, Han, Qing, Ke, Haoqin, Ren, Bingzhong, Wang, Yinliang
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Animals; Aquaporin; Aquaporins - chemistry; Aquaporins - genetics; Aquaporins - metabolism; ar/R selectivity filter; Bombus terrestris; Cold stress; Cold-Shock Response; Functional assay; Insect Proteins - chemistry; Insect Proteins - genetics; Insect Proteins - metabolism; Models, Molecular; NPA motif; Oocytes - metabolism; Phylogeny; Structure-Activity Relationship; Water - chemistry; Water - metabolism; Xenopus laevis
• ISSN: 0141-8130; 1879-0003; 1879-0003
• DOI: 10.1016/j.ijbiomac.2024.133692

Bombus terrestris are efficient pollinators in forestry and agriculture, with higher cold tolerance than other bees. Yet, their cold tolerance mechanism remains unclear. Aquaporins (AQPs) function as cell membrane proteins facilitating rapid water flow, aiding in osmoregulation. Recent studies highlight the importance of insect AQPs in dehydration and cold stress. Comparative transcriptome analysis of B. terrestris under cold stress revealed up-regulation of four AQPs, indicating their potential role in cold tolerance. Seven AQPs—Eglp1, Eglp2, Eglp3, DRIP, PRIP, Bib, and AQP12L—have been identified in B. terrestris. These are widely expressed in various tissues, particularly in the alimentary canal and Malpighian tubules. Functional analysis of BterAQPs in the Xenopus laevis oocytes expressing system showed distinct water and glycerol selectivity, with BterDrip exhibiting the highest water permeability. Molecular modeling of BterDrip revealed six transmembrane domains, two NPA motifs, and an ar/R constriction region (Phe131, His256, Ser265, and Arg271), likely contributing to its water selectivity. Silencing BterDRIP accelerated mortality in B. terrestris under cold stress, highlighting the crucial role of BterDRIP in their cold tolerance and providing a molecular mechanism for their cold adaptation. [Display omitted] •The majority of BterAQPs are highly expressed in Malpighian tube.•BterDRIP permeates water exclusively and most efficiently.•BterDrip has conserved NPA sites and ar/R filters.•BterDrip improves the cold tolerance of Bombus terrestris.