Proteomic Analysis of the Secretory Response of Aspergillus niger to D-Maltose and D-Xylose

• Type: Article in International Scientific Journal
• Date: 2011

Authors

de Oliveira, JMPF (Author) Other; van Passel, MWJ (Author) Other; Schaap, PJ (Author) Other; de Graaff, LH (Author) Other

Journal

Title: PLoS ONE

Vol. 6 No. 8

ISSN: 1932-6203

Publisher: Public Library of Science

Indexing

ISI Web of Knowledge - 33 Citations

Scopus - 45 Citations

Other information

Authenticus ID: P-00F-X0J

DOI: 10.1371/journal.pone.0020865

Abstract (EN): Fungi utilize polysaccharide substrates through extracellular digestion catalyzed by secreted enzymes. Thus far, protein secretion by the filamentous fungus Aspergillus niger has mainly been studied at the level of individual proteins and by genome and transcriptome analyses. To extend these studies, a complementary proteomics approach was applied with the aim to investigate the changes in secretome and microsomal protein composition resulting from a shift to a high level secretion condition. During growth of A. niger on D-sorbitol, small amounts of D-maltose or D-xylose were used as inducers of the extracellular amylolytic and xylanolytic enzymes. Upon induction, protein compositions in the extracellular broth as well as in enriched secretory organelle (microsomal) fractions were analyzed using a shotgun proteomics approach. In total 102 secreted proteins and 1,126 microsomal proteins were identified in this study. Induction by D-maltose or D-xylose resulted in the increase in specific extracellular enzymes, such as glucoamylase A on D-maltose and b-xylosidase D on D-xylose, as well as of microsomal proteins. This reflects the differential expression of selected genes coding for dedicated extracellular enzymes. As expected, the addition of extra D-sorbitol had no effect on the expression of carbohydrate-active enzymes, compared to addition of D-xylose or D-maltose. Furthermore, D-maltose induction caused an increase in microsomal proteins related to translation (e.g., Rpl15) and vesicular transport (e. g., the endosomal-cargo receptor Erv14). Millimolar amounts of the inducers D-maltose and D-xylose are sufficient to cause a direct response in specific protein expression levels. Also, after induction by D-maltose or D-xylose, the induced enzymes were found in microsomes and extracellular. In agreement with our previous findings for D-xylose induction, D-maltose induction leads to recruitment of proteins involved in proteasome-mediated degradation.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 9