Contributions of the Human Cytomegalovirus U30-Associated Open Reading Frames to Infection.

Transposon-based insertional mutagenesis screens have assessed how disruption of numerous human cytomegalovirus (HCMV) open reading frames (ORFs) impacts viral replication. Insertional mutagenesis of the HCMV U30 gene was previously found to substantially inhibit production of viral progeny. However, there are a number of putative U30-associated ORFs, and it is unclear how they impact viral replication.

The Human Cytomegalovirus UL38 protein drives mTOR-independent metabolic flux reprogramming by inhibiting TSC2.

Human Cytomegalovirus (HCMV) infection induces several metabolic activities that are essential for viral replication. Despite the important role that this metabolic modulation plays during infection, the viral mechanisms involved are largely unclear. We find that the HCMV UL38 protein is responsible for many aspects of HCMV-mediated metabolic activation, with UL38 being necessary and sufficient to drive glycolytic activation and induce the catabolism of specific amino acids.

Cofactor activity in factor VIIIa of the blood clotting pathway is stabilized by an interdomain bond between His281 and Ser524 formed in factor VIII.

The factor VIII (FVIII) crystal structure suggests a possible bonding interaction of His(281) (A1 domain) with Ser(524) (A2 domain), although the resolution of the structure (∼4 Å) does not firmly establish this bonding. To establish that side chains of these residues participate in an interdomain bond, we prepared and examined the functional properties of a residue swap variant (H281S/S524H) where His(281) and Ser(524) residues were exchanged with one another and a disulfide-bridged variant (H281C/S524C) where the two residues were replaced with Cys. The latter variant showed efficient disulfide bonding of the A1 and A2 domains.