Open AccessMSP 22.8 is a protease inhibitor‐like protein involved in shell mineralization in the edible mussel Mytilus galloprovincialis
Author(s) -
CalvoIglesias Juan,
PérezEstévez Daniel,
GonzálezFernández África
Publication year - 2017
Publication title -
febs open bio
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.718
H-Index - 31
ISSN - 2211-5463
DOI - 10.1002/2211-5463.12286
Subject(s) - mytilus , mussel , biology , blue mussel , mantle (geology) , biochemistry , fishery , paleontology
The mussel shell protein 22.8 ( MSP 22.8) is recognized by a monoclonal antibody (M22.8) directed against larvae of the mussel Mytilus galloprovincialis . After being secreted by cells of the mantle‐edge epithelium into the extrapallial (EP) space (the gap between the mantle and the shell), the protein is detected in the extrapallial fluid (EPF) and EP hemocytes and finally becomes part of the shell matrix framework in adult specimens of M. galloprovincialis . In the work described here, we show how MSP 22.8 is detected in EPF samples from different species of mussels ( M. galloprovincialis , Mytilus edulis , and Xenostrobus securis ), and also as a shell matrix protein in M. galloprovincialis , Mytilus chilensis , and Perna canaliculus . A multistep purification strategy was employed to isolate the protein from the EPF, which was then analyzed by mass spectrometry in order to identify it. The results indicate that MSP 22.8 is a serpin‐like protein that has great similarity with the protease inhibitor‐like protein‐B1, reported previously for Mytilus coruscus . We suggest that MSP 22.8 is part of a system offering protection from proteolysis during biomineralization and is also part of the innate immune system in mussels.