In the context of signal transduction and tissue homeostasis, what is the significance of gap junctions, and which proteins primarily compose these junctions?

Gap junctions - Composed of claudins and occludins, they prevent the passage of signaling molecules between adjacent cells, thereby isolating cellular responses.

Gap junctions - Composed of connexins, they allow direct cytoplasmic exchange of ions and small molecules, facilitating coordinated cellular responses.

Gap junctions - Composed of desmogleins and desmocollins, they anchor cells to each other and transmit mechanical signals.

Gap junctions - Composed of cadherins, they maintain adhesion and signal transduction by linking actin filaments across cells.