C. Westberg et al., A novel shuttle protein binds to RNA helicase A and activates the retroviral constitutive transport element, J BIOL CHEM, 275(28), 2000, pp. 21396-21401
The constitutive transport element (CTE) of type D retroviruses mediates th
e nuclear export of unspliced viral transcripts. We previously showed that
RNA helicase A functionally interacts with CTE and contains a bidirectional
nuclear transport domain at the carboxyl terminus. Here we report the iden
tification of a novel human protein, helicase A-binding protein 95 (HAP95),
which specifically binds to the carboxyl terminus of RNA helicase A HAP95
is partially homologous to AKAP95, a member of the A kinase-anchoring prote
in family, but lacks the protein kinase A binding domain characteristic of
this family. HAP95 is a nuclear protein at steady state but shuttles betwee
n the nucleus and cytoplasm. Overexpression of HAP95 significantly increase
s CTE-dependent gene expression but has no effect on general gene expressio
n or that mediated by the Rev/Rev response element of human immunodeficienc
y virus type 1.