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A transglutaminase 2-like gene from sea cucumber Apostichopus japonicus mediates coelomocytes autophagy
- Source :
- Fish & Shellfish Immunology. 119:602-612
- Publication Year :
- 2021
- Publisher :
- Elsevier BV, 2021.
-
Abstract
- Transglutaminases (TGases) are widely known to play critical roles in innate immunity, in particular, TGase2, which involves in autophagy process to help degrade protein aggregates under stressful conditions in mammals. Nevertheless, the function of the TGase2 counterpart whether involves in invertebrate autophagy is largely unknown. In this study, a novel TGase2-like homologous gene from the sea cucumber Apostichopus japonicus (named as AjTGase2-like) was cloned using RACE technology and its biological functions were also investigated. The AjTGase2-like gene encoded a peptide of 750 amino acids with the representative domains of Transglut_N domain, TGc domain, and two Transglut_C domains, which exhibited highly conservative with vertebrate TGase2. Multiple sequence alignments and phylogenetic analysis both supported that AjTGase2-like belonged to a new member of TGase2 subfamily. AjTGase2-like was pervasively expressed in all examined tissues, with the largest transcription in muscle, followed by respiratory trees, and intestine. After immersion infection with Vibrio splendidus, the mRNA and protein levels of AjTGase2-like were both significantly induced and reached the highest levels at 24 h, indicating AjTGase2-like plays a key role in immune response. Further functional analysis showed that the ubiquitinated protein level was significantly increased by 1.65-fold (p 0.01) after silencing of AjTGase2-like, and the protein levels of AjLC3-II/I and AjBeclin1 were both obviously decreased by 0.49-fold (p 0.01) and 0.64-fold (p 0.01) at the same time, while the authophagy receptor of Ajp62 was signally up-regulated by 1.40-fold (p 0.01) under same condition. Moreover, the immunofluorescence signals of AjLC3 and Ajp62 were consistent with their protein levels, suggesting knockdown of AjTGase2-like causes a blockage in autophagy. More importantly, the AjLC3 positive signal was not increased after adding with chloroquine in the case of AjTGase2-like interference, indicating AjTGase2-like might play pivotal role in the early step of autophagosome formation. Besides, our results showed that the fluorescence signal of AjTGase2-like was largely co-localized with Ajp62 around the cytoplasm in vivo, and rAjp62 could directly combine with rAjTGase2-like in vitro, indicating AjTGase2-like interacts with Ajp62 during autophagy. Overall, our findings supported that AjTGase2-like served as a positive regulator in sea cucumber authophay.
- Subjects :
- Subfamily
Tissue transglutaminase
Sea Cucumbers
Aquatic Science
Transcription (biology)
Autophagy
Animals
Environmental Chemistry
Protein Glutamine gamma Glutamyltransferase 2
Amino Acid Sequence
Gene
Phylogeny
Vibrio
Messenger RNA
Innate immune system
Base Sequence
biology
General Medicine
biology.organism_classification
Immunity, Innate
Cell biology
Gene Expression Regulation
Stichopus
Apostichopus japonicus
biology.protein
Subjects
Details
- ISSN :
- 10504648
- Volume :
- 119
- Database :
- OpenAIRE
- Journal :
- Fish & Shellfish Immunology
- Accession number :
- edsair.doi.dedup.....267218042a1938039121fa356e8d0187