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Valentini P, Akula S, Alvarado-Vazquez A, Hallgren J, Fu Z, Racicot B, Braasch I, Thorpe M, Hellman L. Extended Cleavage Specificity of two Hematopoietic Serine Proteases from a Ray-Finned Fish, the Spotted Gar ( Lepisosteus oculatus). Int J Mol Sci 2024; 25:1669. [PMID: 38338947 PMCID: PMC10855939 DOI: 10.3390/ijms25031669] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2024] [Revised: 01/23/2024] [Accepted: 01/26/2024] [Indexed: 02/12/2024] Open
Abstract
The extended cleavage specificities of two hematopoietic serine proteases originating from the ray-finned fish, the spotted gar (Lepisosteus oculatus), have been characterized using substrate phage display. The preference for particular amino acids at and surrounding the cleavage site was further validated using a panel of recombinant substrates. For one of the enzymes, the gar granzyme G, a strict preference for the aromatic amino acid Tyr was observed at the cleavable P1 position. Using a set of recombinant substrates showed that the gar granzyme G had a high selectivity for Tyr but a lower activity for cleaving after Phe but not after Trp. Instead, the second enzyme, gar DDN1, showed a high preference for Leu in the P1 position of substrates. This latter enzyme also showed a high preference for Pro in the P2 position and Arg in both P4 and P5 positions. The selectivity for the two Arg residues in positions P4 and P5 suggests a highly specific substrate selectivity of this enzyme. The screening of the gar proteome with the consensus sequences obtained by substrate phage display for these two proteases resulted in a very diverse set of potential targets. Due to this diversity, a clear candidate for a specific immune function of these two enzymes cannot yet be identified. Antisera developed against the recombinant gar enzymes were used to study their tissue distribution. Tissue sections from juvenile fish showed the expression of both proteases in cells in Peyer's patch-like structures in the intestinal region, indicating they may be expressed in T or NK cells. However, due to the lack of antibodies to specific surface markers in the gar, it has not been possible to specify the exact cellular origin. A marked difference in abundance was observed for the two proteases where gar DDN1 was expressed at higher levels than gar granzyme G. However, both appear to be expressed in the same or similar cells, having a lymphocyte-like appearance.
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Affiliation(s)
- Paolo Valentini
- Department of Cell and Molecular Biology, Uppsala University, P.O. Box 596, SE-751 24 Uppsala, Sweden; (P.V.); (S.A.); (Z.F.); (M.T.)
| | - Srinivas Akula
- Department of Cell and Molecular Biology, Uppsala University, P.O. Box 596, SE-751 24 Uppsala, Sweden; (P.V.); (S.A.); (Z.F.); (M.T.)
| | - Abigail Alvarado-Vazquez
- Department of Medical Biochemistry and Microbiology, Uppsala University Biomedical Centre (BMC), P.O. Box 582, SE-751 23 Uppsala, Sweden; (A.A.-V.); (J.H.)
| | - Jenny Hallgren
- Department of Medical Biochemistry and Microbiology, Uppsala University Biomedical Centre (BMC), P.O. Box 582, SE-751 23 Uppsala, Sweden; (A.A.-V.); (J.H.)
| | - Zhirong Fu
- Department of Cell and Molecular Biology, Uppsala University, P.O. Box 596, SE-751 24 Uppsala, Sweden; (P.V.); (S.A.); (Z.F.); (M.T.)
| | - Brett Racicot
- Department of Integrative Biology, Michigan State University, East Lansing, MI 48825, USA; (B.R.); (I.B.)
| | - Ingo Braasch
- Department of Integrative Biology, Michigan State University, East Lansing, MI 48825, USA; (B.R.); (I.B.)
- Ecology, Evolution and Behavior Program, Michigan State University, East Lansing, MI 48825, USA
| | - Michael Thorpe
- Department of Cell and Molecular Biology, Uppsala University, P.O. Box 596, SE-751 24 Uppsala, Sweden; (P.V.); (S.A.); (Z.F.); (M.T.)
| | - Lars Hellman
- Department of Cell and Molecular Biology, Uppsala University, P.O. Box 596, SE-751 24 Uppsala, Sweden; (P.V.); (S.A.); (Z.F.); (M.T.)
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