Читать книгу Introduction to the Human Cell - Danton PhD O'Day - Страница 22

Cell junctions are made up of many proteins with diverse functions. Often Junctional Adhesion Molecules (JAMs) are related to other protein isoforms or variants that appear in other contexts (e.g., cadherins and integrins function as JAMs and as individual cell adhesion molecules). In contrast, some junctions contain unique proteins (e.g., connexin proteins of gap junctions).

In the following figure, notice that cadherins are involved in cell-cell adhesion as part of desmosomes and adherens junctions while integrins mediate cell-substratum adhesions via hemi-desmosomes and focal adhesions (Figure 3.4). As discussed in the next chapter, cadherins and integrins are also cell adhesion molecules that function independently from their role in cell junctions. Thus certain proteins can serve dual or even multiple functions in a cell. More often than not, the specific cell adhesion proteins (e.g., cadherins, integrins) are variant proteins either coded for by another gene or resulting from post-translational modifications once the gene has been transcribed as will be covered in the next chapter.

Figure 3.4. Types of cell and junctional adhesion proteins.