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CmCatD, a cathepsin D-like protease has a potential role in insect defense against a phytocystatin.
J Insect Physiol. 2009 Aug; 55(8):678-85.JI

Abstract

When fed on a diet containing a proteinaceous cysteine protease inhibitor from soybean (scN), cowpea bruchid larvae enhance their overall digestive capacity to counter the inhibitory effect. Elevated proteolytic activity is attributed not only to the major digestive cysteine proteases (CmCPs), but also to aspartic proteases, a minor midgut protease component. In this study, we isolated a CmCatD cDNA from cowpea bruchid midgut that shares substantial sequence similarity with cathepsin D-like aspartic proteases of other organisms. Its transcript profile was developmentally regulated and subject to alteration by dietary scN. CmCatD transcripts were more abundant in scN-fed 3rd and 4th instar midguts than in control. The bacterially expressed recombinant CmCatD proprotein was capable of autoprocessing under acidic conditions, and mature CmCatD also exhibited pH-dependent proteolytic activity which was inhibited specifically by pepstatin A, indicative of its aspartic protease nature. CmCatD trans-activated CmCPs and vice versa, suggesting a cooperation between the minor midgut CmCatD and major digestive CmCPs. Further, CmCatD was able to degrade scN after extensive incubation. This activity partially restored CmCP proteolytic activity otherwise inhibited by scN. Thus CmCatD could facilitate insects' coping with the challenge of dietary scN by exerting its scN-insensitive and scN-degrading activity, freeing cysteine proteases for food degradation. Taken together, cowpea bruchids coordinate the functionality of the two classes of digestive proteases to fend off the negative effect of scN, and fulfill their nutrient requirements.

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Authors+Show Affiliations

Ahn JE
Department of Entomology, Texas A&M University, College Station, TX 77843, USA.
Zhu-Salzman K
No affiliation info available

MeSH

Amino Acid SequenceAnimalsAspartic Acid EndopeptidasesCathepsin DColeopteraCystatinsCysteine EndopeptidasesDigestive SystemEnzyme InhibitorsEnzyme StabilityGene Expression Regulation, EnzymologicInsect ProteinsMolecular Sequence DataSequence AlignmentSoybean Proteins

Pub Type(s)

Journal Article
Research Support, U.S. Gov't, Non-P.H.S.

Language

eng

PubMed ID

19446566

Citation

Ahn, Ji-Eun, and Keyan Zhu-Salzman. "CmCatD, a Cathepsin D-like Protease Has a Potential Role in Insect Defense Against a Phytocystatin." Journal of Insect Physiology, vol. 55, no. 8, 2009, pp. 678-85.
Ahn JE, Zhu-Salzman K. CmCatD, a cathepsin D-like protease has a potential role in insect defense against a phytocystatin. J Insect Physiol. 2009;55(8):678-85.
Ahn, J. E., & Zhu-Salzman, K. (2009). CmCatD, a cathepsin D-like protease has a potential role in insect defense against a phytocystatin. Journal of Insect Physiology, 55(8), 678-85. https://doi.org/10.1016/j.jinsphys.2009.04.016
Ahn JE, Zhu-Salzman K. CmCatD, a Cathepsin D-like Protease Has a Potential Role in Insect Defense Against a Phytocystatin. J Insect Physiol. 2009;55(8):678-85. PubMed PMID: 19446566.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - CmCatD, a cathepsin D-like protease has a potential role in insect defense against a phytocystatin. AU - Ahn,Ji-Eun, AU - Zhu-Salzman,Keyan, Y1 - 2009/05/26/ PY - 2009/03/31/received PY - 2009/04/26/revised PY - 2009/04/29/accepted PY - 2009/5/19/entrez PY - 2009/5/19/pubmed PY - 2009/9/9/medline SP - 678 EP - 85 JF - Journal of insect physiology JO - J Insect Physiol VL - 55 IS - 8 N2 - When fed on a diet containing a proteinaceous cysteine protease inhibitor from soybean (scN), cowpea bruchid larvae enhance their overall digestive capacity to counter the inhibitory effect. Elevated proteolytic activity is attributed not only to the major digestive cysteine proteases (CmCPs), but also to aspartic proteases, a minor midgut protease component. In this study, we isolated a CmCatD cDNA from cowpea bruchid midgut that shares substantial sequence similarity with cathepsin D-like aspartic proteases of other organisms. Its transcript profile was developmentally regulated and subject to alteration by dietary scN. CmCatD transcripts were more abundant in scN-fed 3rd and 4th instar midguts than in control. The bacterially expressed recombinant CmCatD proprotein was capable of autoprocessing under acidic conditions, and mature CmCatD also exhibited pH-dependent proteolytic activity which was inhibited specifically by pepstatin A, indicative of its aspartic protease nature. CmCatD trans-activated CmCPs and vice versa, suggesting a cooperation between the minor midgut CmCatD and major digestive CmCPs. Further, CmCatD was able to degrade scN after extensive incubation. This activity partially restored CmCP proteolytic activity otherwise inhibited by scN. Thus CmCatD could facilitate insects' coping with the challenge of dietary scN by exerting its scN-insensitive and scN-degrading activity, freeing cysteine proteases for food degradation. Taken together, cowpea bruchids coordinate the functionality of the two classes of digestive proteases to fend off the negative effect of scN, and fulfill their nutrient requirements. SN - 1879-1611 UR - https://www.unboundmedicine.com/medline/citation/19446566/CmCatD_a_cathepsin_D_like_protease_has_a_potential_role_in_insect_defense_against_a_phytocystatin_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S0022-1910(09)00206-6 DB - PRIME DP - Unbound Medicine ER -