Jo et al. uncover the role of a spliceosome component in removing retained introns in Arabidopsis in response to heat stress https://doi.org/10.1093/plcell/koac084
Background: Alternative splicing plays a key role in abiotic stress responses in plants, especially responses to heat stress. The spliceosome is a protein complex that functions in pre-mRNA splicing, leading to the formation of mature mRNA. Nuclear cyclophilins (CYPs) are referred to as spliceophilins because they mechanistically associate with spliceosomal components. A few human spliceophilins are known to have specific functions in regulating spliceosomal proteins through post-translational modification. However, whether plant spliceophilins are involved in pre-mRNA splicing and heat stress responses remains unknown.
Question: How does the spliceophilin CYP18-1 function in pre-mRNA splicing and heat stress acclimation in Arabidopsis?
Findings: CYP18-1 is crucial for plant adaptation to heat stress during germination. In addition, CYP18-1 interacts with spliceosome complex C proteins and facilitates the dephosphorylation of the splicing factor PRP18a in cooperation with the phosphatase PP2A BʹȠ. The loss-of-function of CYP18-1 causes a splicing deficiency under heat stress and leads to thermosensitivity.
Next steps: It is important to elucidate whether the phosphorylation status of PRP18a affects heat stress acclimation. Also, since CYP18-1 gene expression increases in response to abiotic stress in addition to heat stress, we want to know whether CYP18-1 functions in other abiotic stress responses. Finally, since CYP18-1 is located in both the nucleus and cytosol, we would like to reveal its functions in the cytosol.
Seung Hee Jo, Hyun Ji Park, Areum Lee, Haemyeong Jung, Jeong Mee Park, Suk-Yoon Kwon, Hyun-Soon Kim, Hyo-Jun Lee, Youn-Sung Kim, Choonkyun Jung, Hye Sun Cho (2022). The Arabidopsis cyclophilin CYP18-1 facilitates PRP18 dephosphorylation and the splicing of introns retained under heat stress. https://doi.org/10.1093/plcell/koac084