title: Phosphorylation is required for myosin regulatory light chain (PmMRLC) to control yellow head virus infection in shrimp hemocytes.
abstract: The cellular signal-transduction process is largely controlled by protein phosphorylation. Shrimp infected with yellow head virus show dramatic changes in their hemocyte phosphoproteomic patterns, and aberrant activation of phosphorylation-based signaling networks has been implicated in a number of diseases. In this study, we focused on phosphorylation of Penaeus monodon myosin regulatory light chain (PmMRLC) that is induced at an early hour post YHV infection and is concomitant with cellular actin remodeling. In shrimp cell cultures, this phosphorylation was inhibited by the myosin light chain kinase (MLCK) inhibitors ML-7 and ML-9, suggesting that PmMLC phosphorylation is MLCK pathway-dependent. Blocking PmMRLC phosphorylation resulted in increased replication of YHV and reduction of phagocytic activities of shrimp hemocytes called semigranular cells (SGC) and granular cells (GC). Injection of MLCK inhibitors prior to YHV challenge resulted in dose-dependent elevation in quantity of YHV-positive GC and cytoplasmic YHV protein, coincident with high shrimp mortality. Altogether, we demonstrated that PmMRLC phosphorylation increases after YHV infection in shrimp and that inhibition of the phosphorylation leads to increased YHV replication, reduced hemocyte phagocytic activity (probably through actin remodeling) and subsequent shrimp death. Thus, further studies on the MLCK activation pathway may lead to new strategies in development and implementation of therapy for YHV infections in shrimp.
authors: Institute of Molecular Biosciences, Mahidol University, Salaya Campus, Salaya, Nakhonpathom 73170, Thailand.
authors: Suparat
authors: S
authors: Taengchaiyaphum
authors: Phattara-orn
authors: PO
authors: Havanapan
authors: Sittiruk
authors: S
authors: Roytrakul
authors: Chu-Fang
authors: CF
authors: Lo
authors: Kallaya
authors: K
authors: Sritunyalucksana
authors: Chartchai
authors: C
authors: Krittanai
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D015153:Blotting, Western; D002853:Chromatography, Liquid; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics / Q000378:metabolism; D015180:Electrophoresis, Gel, Two-Dimensional; D005455:Fluorescent Antibody Technique; D006434:Hemocytes / Q000737:chemistry / Q000378:metabolism / Q000821:virology; D008969:Molecular Sequence Data; D018994:Myosin Light Chains / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D033561:Penaeidae / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism / Q000821:virology*; D010750:Phosphoproteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D010766:Phosphorylation; D010802:Phylogeny; D020543:Proteome / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D046828:Roniviridae / Q000276:immunology; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D053719:Tandem Mass Spectrometry
chemical_list: D018076:DNA, Complementary; D018994:Myosin Light Chains; D010750:Phosphoproteins; D020543:Proteome; D012333:RNA, Messenger