1EJP

SOLUTION STRUCTURE OF THE SYNDECAN-4 WHOLE CYTOPLASMIC DOMAIN

Summary for 1EJP

• Entry DOI: 10.2210/pdb1ejp/pdb
• Related: 1EJQ
• NMR Information: BMRB: 4591
• Descriptor: SYNDECAN-4 (1 entity in total)
• Functional Keywords: symmetric-parallel-interwinded dimer, signaling protein
• Cellular location: Membrane; Single-pass type I membrane protein: P31431
• Total number of polymer chains: 2
• Total formula weight: 6629.70

Authors

Lee, D.,Oh, E.S.,Woods, A.,Couchman, J.R.,Lee, W. (deposition date: 2000-03-03, release date: 2001-09-19, Last modification date: 2024-05-22)

Primary citation

Shin, J.,Lee, W.,Lee, D.,Koo, B.K.,Han, I.,Lim, Y.,Woods, A.,Couchman, J.R.,Oh, E.S.
Solution structure of the dimeric cytoplasmic domain of syndecan-4.
Biochemistry, 40:8471-8478, 2001

PubMed Abstract: The syndecans, transmembrane proteoglycans which are involved in the organization of cytoskeleton and/or actin microfilaments, have important roles as cell surface receptors during cell-cell and/or cell-matrix interactions. Since previous studies indicate that the function of the syndecan-4 cytoplasmic domain is dependent on its oligomeric status, the conformation of the syndecan-4 cytoplasmic domain itself is important in the understanding of its biological roles. Gel filtration results show that the syndecan-4 cytoplasmic domain (4L) itself forms a dimer stabilized by ionic interactions between peptides at physiological pH. Commensurately, the NMR structures demonstrate that syndecan-4L is a compact intertwined dimer with a symmetric clamp shape in the central variable V region with a root-mean-square deviation between backbone atom coordinates of 0.95 A for residues Leu(186)-Ala(195). The molecular surface of the 4L dimer is highly positively charged. In addition, no intersubunit NOEs in membrane proximal amino acid resides (C1 region) have been observed, demonstrating that the C1 region is mostly unstructured in the syndecan-4L dimer. Interestingly, two parallel strands of 4L form a cavity in the center of the dimeric twist similar to our previously reported 4V structure. The overall topology of the central variable region within the 4L structure is very similar to that of 4V complexed with the phosphatidylinositol 4,5-bisphosphate; however, the intersubunit interaction mode is affected by the presence of C1 and C2 regions. Therefore, we propose that although the 4V region in the full cytoplasmic domain has a tendency for strong peptide--peptide interaction, it may not be enough to overcome the repulsion of the C1 regions of syndecan-4L.

PubMed: 11456484
DOI: 10.1021/bi002750r

Experimental method

SOLUTION NMR