A protein called GEF-H 1 is known to control immune responses to certain viruses such as influenza A. GEF-H 1 is best classified as which kind of protein?

GEF-H1 is a guanine nucleotide exchange factor. It helps activate signaling proteins by promoting the exchange of GDP for GTP, so it functions as an enzyme. It is not an antibody or a structural protein.

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