Further biochemical characterization of Mycobacterium leprae laminin-binding proteins.
It has been demonstrated that the alpha2 chain of laminin-2 present on the surface of Schwann cells is involved in the process of attachment of Mycobacterium leprae to these cells. Searching for M. leprae laminin-binding molecules, in a previous study we isolated and characterized the cationic proteins histone-like protein (Hlp) and ribosomal proteins S4 and S5 as potential adhesins involved in M. leprae-Schwann cell interaction. Hlp was shown to bind alpha2-laminins and to greatly enhance the attachment of mycobacteria to ST88-14 Schwann cells. In the present study, we investigated the laminin-binding capacity of the ribosomal proteins S4 and S5. The genes coding for these proteins were PCR amplified and their recombinant products were shown to bind alpha2-laminins in overlay assays. However, when tested in ELISA-based assays and in adhesion assays with ST88-14 cells, in contrast to Hlp, S4 and S5 failed to bind laminin and act as adhesins. The laminin-binding property and adhesin capacity of two basic host-derived proteins were also tested, and only histones, but not cytochrome c, were able to increase bacterial attachment to ST88-14 cells. Our data suggest that the alanine/lysine-rich sequences shared by Hlp and eukaryotic H1 histones might be involved in the binding of these cationic proteins to laminin.
Marques
M A
MA
Laboratório de Hanseníase, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Av. Brasil, 4365, 21045-000 Rio de Janeiro, RJ, Brazil.
Mahapatra
S
S
Sarno
E N
EN
Santos
S
S
Spencer
J S
JS
Brennan
P J
PJ
Pessolani
M C
MC
D000818:Animals; D001135:Armadillos; D001422:Bacterial Adhesion / Q000502:physiology; D001426:Bacterial Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D003001:Cloning, Molecular; D004591:Electrophoresis, Polyacrylamide Gel; D004797:Enzyme-Linked Immunosorbent Assay; D004926:Escherichia coli / Q000235:genetics; D006657:Histones / Q000378:metabolism; D006801:Humans; D007797:Laminin / Q000378:metabolism*; D009166:Mycobacterium leprae / Q000737:chemistry* / Q000235:genetics; D016133:Polymerase Chain Reaction; D011485:Protein Binding / Q000502:physiology; D012269:Ribosomal Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D012583:Schwann Cells / Q000382:microbiology / Q000502:physiology
D001426:Bacterial Proteins; D006657:Histones; D007797:Laminin; D012269:Ribosomal Proteins; C031798:ribosomal protein S4; C030831:ribosomal protein S5