CgRab1 regulates Cgcathepsin L1 expression and participates in the phagocytosis of haemocytes in oyster Crassostrea gigas. Issue 120 (January 2022)

• Record Type: Journal Article
• Authors: Liu, Yu; Wang, Weilin; Li, Chenghua; Li, Meijia; Zhang, Chi; Dong, Miren; Wang, Lingling; Song, Linsheng
• Is Part Of: Fish & shellfish immunology. Issue 120(2022)
• Page Start: 536
• Page End: 546
• Publication Date: 2022-01
• Subjects: Crassostrea gigas -- Rab1 -- GTP -- cathepsinL1 -- Phagocytosis; Fishes -- Immunology -- Periodicals; Shellfish -- Immunology -- Periodicals; Poissons -- Immunologie -- Périodiques; Crustacés -- Immunologie -- Périodiques; 571.9617
• DOI: 10.1016/j.fsi.2021.12.031
• Languages: English
• ISSNs: 1050-4648

Abstract

Abstract: Rab protein plays an important role in a variety of cellular activities, especially the fusion process of the inner membrane during endocytosis. In the present study, a Rab1 protein ( Cg Rab1) was identified from the Pacific oyster Crassostrea gigas. The full-length cDNA sequence of Cg Rab1 was of 2248 bp with an open reading frame of 618 bp, encoding a polypeptide of 205 amino acids containing a Rab domain. The deduced amino acid sequence of Cg Rab1 shared 94.2% and 89.3% identity with Rab1 from Pomacea canaliculata and Homo sapiens respectively. In the phylogenetic tree, Cg Rab1 was firstly clustered with the Rab1s from Aplysia californica and Pomacea canaliculata to form a sister group with Rab1 from invertebrates. The recombinant Cg Rab1 protein (r Cg Rab1) was able to bind GTP. The mRNA transcripts of Cg Rab1 were highly expressed in oyster haemocytes, and its expression level in oyster haemocytes was significantly up-regulated at 24 h after the stimulations with Vibro splendidus, which was 2.43-fold ( p < 0.01) of that in the control group. After the expression of Cg Rab1 was knocked down (0.38-fold of that in EGFP-RNAi experimental group) by RNAi，the protein expression of Cg cathepsin L1 were reduced (0.63-fold, p < 0.01) compared with that in EGFP-RNAi experimental group. The phagocytic rate and phagocytic index of haemocytes in Cg Rab1-RNAi oysters decreased after V. splendidus stimulation, which was 0.50-fold ( p < 0.01) and 0.58-fold ( p < 0.01) of that in EGFP-RNAi experimental group. These results indicated that Cg Rab1 was involved in the process of haemocytes phagocytosis by regulating the expression of Cg cathepsin L1 in oyster C. gigas . Highlights: A Rab1 homologue protein (CgRab1) was identified from oyster Crassostrea gigas. CgRab1 mRNA expression level in haemocytes was up-regulated after V. splendidus stimulation. The recombinant protein of CgRab1 was able to bind GTP in vitro. CgRab1 regulated the expression of CgcathepsinL1 and involved in the phagocytosis of haemocytes.