Endocytosis and nuclear trafficking of adeno-associated virus type 2 are controlled by rac1 and phosphatidylinositol-3 kinase activation.
Adeno-associated virus (AAV) is a single-stranded DNA parvovirus that causes no currently known pathology in humans. Despite the fact that this virus is of increasing interest to molecular medicine as a vector for gene delivery, relatively little is known about the cellular mechanisms controlling infection. In this study, we have examined endocytic and intracellular trafficking of AAV-2 using fluorescent (Cy3)-conjugated viral particles and molecular techniques. Our results demonstrate that internalization of heparan sulfate proteoglycan-bound AAV-2 requires alphaVbeta5 integrin and activation of the small GTP-binding protein Rac1. Following endocytosis, activation of a phosphatidylinositol-3 (PI3) kinase pathway was necessary to initiate intracellular movement of AAV-2 to the nucleus via both microfilaments and microtubules. Inhibition of Rac1 using a dominant N17Rac1 mutant led to a decrease in AAV-2-mediated PI3 kinase activation, indicating that Rac1 may act proximal to PI3 kinase during AAV-2 infection. In summary, our results indicate that alphaVbeta5 integrin-mediated endocytosis of AAV-2 occurs through a Rac1 and PI3 kinase activation cascade, which directs viral movement along the cytoskeletal network to the nucleus.
Sanlioglu
S
S
Department of Anatomy and Cell Biology and Center for Gene Therapy, University of Iowa College of Medicine, Iowa City, Iowa 52242, USA.
Benson
P K
PK
Yang
J
J
Atkinson
E M
EM
Reynolds
T
T
Engelhardt
J F
JF
D001692:Biological Transport / Q000502:physiology; D000229:Dependovirus / Q000502:physiology*; D006367:HeLa Cells; D006801:Humans; D019869:Phosphatidylinositol 3-Kinases / Q000502:physiology*; D015398:Signal Transduction; D014779:Virus Replication / Q000502:physiology*; D020830:rac1 GTP-Binding Protein / Q000502:physiology*
D019869:Phosphatidylinositol 3-Kinases; D020830:rac1 GTP-Binding Protein