Syndecan and integrin interactomes: large complexes in small spaces

• Published in: Current opinion in structural biology Vol. 22; no. 5; pp. 583 - 590
• Main Authors: Roper, James A, Williamson, Rosalind C, Bass, Mark D
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.10.2012; Elsevier Science
• Subjects: adhesion; Focal Adhesions - metabolism; Humans; integrins; Integrins - metabolism; plasma membrane; Protein Binding; Protein Interaction Maps; proteoglycans; Syndecans - metabolism
• ISSN: 0959-440X; 1879-033X; 1879-033X
• DOI: 10.1016/j.sbi.2012.07.003

► Syndecans are cleared from adhesion sites to allow integrin engagement. ► Literature-curated interactomes differ between syndecan-1 and syndecan-4. ► Overlap between interactomes of syndecan or integrin describe adhesion formation. ► Switching of syndecan signalling by phosphorylation. The syndecan family of transmembrane proteoglycans cooperate with integrins to regulate both early and late events in adhesion formation. The heparan sulphate chains substituted on to the syndecan ectodomains are capable of engaging ligands over great distance, while the protein core spans the plasma membrane and initiates cytoplasmic signals through a short cytoplasmic tail. These properties create a spatial paradox. The volume of the heparan sulphate chains greatly exceeds that of the integrins with which it cooperates, while the short cytodomain must bind to multiple cytoplasmic factors, despite being long enough to bind only one or two. In this review we consider the structural rearrangements that a cell undertakes to overcome spatial restrictions and compare the interactomes of syndecans and integrins to gain insight into the composition of adhesions and how they are regulated over time.