A comparative molecular force spectroscopy study of homophilic JAM-A interactions and JAM-A interactions with reovirus attachment protein sigma1.
JAM-A belongs to a family of immunoglobulin-like proteins called junctional adhesion molecules (JAMs) that localize at epithelial and endothelial intercellular tight junctions. JAM-A is also expressed on dendritic cells, neutrophils, and platelets. Homophilic JAM-A interactions play an important role in regulating paracellular permeability and leukocyte transmigration across epithelial monolayers and endothelial cell junctions, respectively. In addition, JAM-A is a receptor for the reovirus attachment protein, sigma1. In this study, we used single molecular force spectroscopy to compare the kinetics of JAM-A interactions with itself and sigma1. A chimeric murine JAM-A/Fc fusion protein and the purified sigma1 head domain were used to probe murine L929 cells, which express JAM-A and are susceptible to reovirus infection. The bond half-life (t(1/2)) of homophilic JAM-A interactions was found to be shorter (k(off)(o) = 0.688 +/- 0.349 s(-1)) than that of sigma1/JAM-A interactions (k(off)(o) = 0.067 +/- 0.041 s(-1)). These results are in accordance with the physiological functions of JAM-A and sigma1. A short bond lifetime imparts a highly dynamic nature to homophilic JAM-A interactions for regulating tight junction permeability while stable interactions between sigma1 and JAM-A likely anchor the virus to the cell surface and facilitate viral entry.
Vedula
Sri Ram Krishna
SR
Nano-Biomechanics Lab, Division of Bioengineering, 9 Engineering Drive 1, National University of Singapore, Singapore 117576, Singapore.
Lim
Tong Seng
TS
Kirchner
Eva
E
Guglielmi
Kristen M
KM
Dermody
Terence S
TS
Stehle
Thilo
T
Hunziker
Walter
W
Lim
Chwee Teck
CT
D000818:Animals; D015815:Cell Adhesion Molecules / Q000737:chemistry*; D007700:Kinetics; D007739:L Cells; D051379:Mice; D018625:Microscopy, Atomic Force; D046912:Multiprotein Complexes; D030102:Orthoreovirus, Mammalian / Q000737:chemistry; D054730:Protein Interaction Domains and Motifs; D017434:Protein Structure, Tertiary; D011956:Receptors, Cell Surface / Q000737:chemistry*; D011993:Recombinant Fusion Proteins / Q000737:chemistry; D017361:Viral Nonstructural Proteins / Q000737:chemistry*
D015815:Cell Adhesion Molecules; C498686:F11r protein, mouse; D046912:Multiprotein Complexes; D011956:Receptors, Cell Surface; D011993:Recombinant Fusion Proteins; D017361:Viral Nonstructural Proteins; C071901:sigma 1NS protein, Reovirus