Protein found in or associated with a host cell junction, a host cell-host cell or host cell-host extracellular matrix contact within a tissue of a host multicellular organism, especially abundant in host epithelia. In vertebrates, there are three major types of cell junctions: anchoring junctions (e.g. adherens junctions), communicating junctions (e.g. gap junctions) and occluding junctions (e.g. tight junctions).