At the cell surface the GAG chains interact with many ligands such as growth factors (GFs), cytokines, adhesion molecules etc. [1], [2], and they are essential modulators of cellular signaling in embryonic development and tumorigenesis [3], [4].
Intracellular profilin-1 interacts with many ligands such as actin, the actin-related protein (Arp 2, gephyrin, phosphatidyl-inositol-4,5-bisphosphate (PIP2), and diverse proteins comprising a poly-proline stretch, i.e. VASP, p140mDia, and neuronal Wiscott-Aldrich-Syndrome protein [12].
Typical native chemotaxis pathway is perfectly adaptive to many ligands, such as aspartate [7], [12], [14], [15] while a minority of native pathways (for example of which detecting O2 [16]) as well as pseudochemotaxis pathways (artificial ones designed to sense certain small molecule [17]) are not adaptive.
The itgav gene encodes a receptor for many ligands, such as fibronectin, fibrinogen, laminin, and MMP-2.
Many ligands such as transferrin, lactoferrin, RGD, and folic acid have been evaluated for enhanced tumor imaging.
Polymeric micelles can be conjugated with many ligands such as antibodies fragments, epidermal growth factors, α2-glycoprotein, transferrin, and folate to target micelles to cancer cells.
As with many other ligands such as prosaposin (41), acid sphingomyelinase (42) and cathepsins D and H (43), evidence suggests SORT1 is a sorting receptor of PGRN for lysosome delivery and degradation (19).
Yet CLRs also recognise carbohydrates, such as β-glucan, and many non-carbohydrate ligands, such as lipids and proteins, through mechanisms that are not yet fully understood [ 1,2].
In many cases, other target ligands, such as lipoproteins or other proteins, are known but in other instances the functions of these domains remain to be established.
In vertebrates, PPARα ligands such as Clo induce many fatty acid beta oxidation and oxidative phosphorylation enzymes [ 44, 45].
Due to these similarities, cadmium can replace zinc in many biological systems, particularly the systems that contain softer ligands such as sulfur.
