Can membrane protein be soluble?

Membrane proteins are also expressed in soluble.

Our wheat germ extract (translation solution) contains wheat germ-derived cell membrane fragments, which act as molecular chaperones and are adsorbed and folded on hydrophobic groups (transmembrane regions) of membrane proteins. And proteins makes soluble..
The lipid fraction has been confirmed by ultra centrifuge of membrane proteins synthesized from our translation solution.

Traditionally, membrane proteins are synthesized in the presence of liposomes, and the resulting proteoliposomes are not soluble.