Endophilins interact with Moloney murine leukemia virus Gag and modulate virion production.
BACKGROUND
The retroviral Gag protein is the central player in the process of virion assembly at the plasma membrane, and is sufficient to induce the formation and release of virus-like particles. Recent evidence suggests that Gag may co-opt the host cell's endocytic machinery to facilitate retroviral assembly and release.


RESULTS
A search for novel partners interacting with the Gag protein of the Moloney murine leukemia virus (Mo-MuLV) via the yeast two-hybrid protein-protein interaction assay resulted in the identification of endophilin 2, a component of the machinery involved in clathrin-mediated endocytosis. We demonstrate that endophilin interacts with the matrix or MA domain of the Gag protein of Mo-MuLV, but not of human immunodeficiency virus, HIV. Both exogenously expressed and endogenous endophilin are incorporated into Mo-MuLV viral particles. Titration experiments suggest that the binding sites for inclusion of endophilin into viral particles are limited and saturable. Knock-down of endophilin with small interfering RNA (siRNA) had no effect on virion production, but overexpression of endophilin and, to a lesser extent, of several fragments of the protein, result in inhibition of Mo-MuLV virion production, but not of HIV virion production.


CONCLUSIONS
This study shows that endophilins interact with Mo-MuLV Gag and affect virion production. The findings imply that endophilin is another component of the large complex that is hijacked by retroviruses to promote virion production.
Wang
Margaret Q
MQ
Department of Microbiology, Columbia University, College of Physicians and Surgeons, New York, NY 10032, USA.
Kim
Wankee
W
Gao
Guangxia
G
Torrey
Ted A
TA
Morse
Herbert C
HC
De Camilli
Pietro
P
Goff
Stephen P
SP
D048868:Adaptor Proteins, Signal Transducing / Q000096:biosynthesis / Q000378:metabolism*; D000818:Animals; D002460:Cell Line; D005786:Gene Expression Regulation / Q000235:genetics; D015683:Gene Products, gag / Q000378:metabolism*; D006801:Humans; D006868:Hydrolysis; D007668:Kidney / Q000166:cytology / Q000196:embryology; D008979:Moloney murine leukemia virus / Q000235:genetics*; D010446:Peptide Fragments / Q000096:biosynthesis; D010447:Peptide Hydrolases / Q000378:metabolism; D051381:Rats; D012190:Retroviridae / Q000235:genetics; D013045:Species Specificity; D014162:Transfection; D022161:Transport Vesicles / Q000737:chemistry / Q000235:genetics; D020798:Two-Hybrid System Techniques; D033921:Vesicular Transport Proteins / Q000378:metabolism; D014771:Virion / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D014779:Virus Replication / Q000235:genetics
D048868:Adaptor Proteins, Signal Transducing; D015683:Gene Products, gag; D010446:Peptide Fragments; C429293:SH3GLB1 protein, human; D033921:Vesicular Transport Proteins; D010447:Peptide Hydrolases