Membrane Transport

Gap junctions consist of Connexins (Cx), a family of proteins that form channels linking the cytoplasm of adjacent cells. All Connexin molecules have four membrane-spanning domains, two extracellular domains, and a cytoplasmic carboxy-terminal tail of varying length that has an important role in the regulation of the gating properties of the channel. Interestingly Connexin 43 also known as gap junction alpha-1 protein is one of the most abundant gap-junction protein.

ABCG2 is a member of the ATP-binding cassette (ABC) transporter superfamily. Among ABC transporters ABCG2 is particularly interesting for its potential role in protecting cancer stem cells and its complex oligomeric structure (1).

ATP-binding cassette superfamily F2 (ABCF2) is a member of the ATP-binding cassette (ABC) transporter superfamily, and more specifically, a member of the GCN20 subfamily. Most members of this family are membrane proteins that transport various substrates across the cell membrane [1, 2].