Biochemical characterization of a novel sphingomyelinase-like protein from the Rhipicephalus microplus tick

Author(s)

Silva, Fernando A. A. ; Costa, Gabriel C. A. ; Parizi, Luis F. ; Vaz Junior, Itabajara da Silva ; Tanaka, Aparecida S.

• Document type: Journal article
• Source: Experimental Parasitology; v. 254, p. 10-pg., 2023-09-13.

Abstract

Sphingomyelinase D is a toxin present in venomous spiders and bacteria and is associated with infection symptoms in patients affected by spider bites. It was observed that in Ixodes scapularis ticks, sphingomyelinaselike protein secreted in saliva can modulate the host immune response, affecting the transmission of flavivirus to the host via exosomes. In this work, a sphingomyelinase D-like protein (RmSMase) from R. microplus, a tick responsible for economic losses and a vector of pathogens for cattle, was investigated. The amino acid sequence revealed the lack of important residues for enzymatic activity, but the recombinant protein showed sphingomyelinase D activity. RmSMase shows Ca2+ and Mg2+ dependence in acidic pH, differing from IsSMase, which has Mg2+ dependence in neutral pH. Due to the difference between RmSMase and other SMases described, the data suggest that RmSMase belongs to SMase D class IIc. RmSMase mRNA transcription levels are upregulated during tick feeding, and the recombinant protein was recognized by host antibodies elicited after heavy tick infestation, indicating that RmSMase is present in tick saliva and may play a role in the tick feeding process. (AU)

• FAPESP's process: 20/02433-5 - Library construction of cDNA fragments of R. microplus proteolytic enzymes (peptidases) and serpins on the surface of filamentous phages
• Grantee: Gabriel Cerqueira Alves Costa
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 12/03657-8 - Inhibitor and proteases of ectoparasites: relationship of structure-function and identification of the role of these molecules in the interaction of diseases vector e their etiological agents
• Grantee: Aparecida Sadae Tanaka
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 19/03779-5 - Use of phage display as a tool in the diagnosis and control of diseases transmitted by hematophagous vectors
• Grantee: Aparecida Sadae Tanaka
• Support Opportunities: Research Projects - Thematic Grants