Secondary PDZ domain-binding site on class B plexins enhances the affinity for PDZâ€"RhoGEF

Heath G. Pascoe, Stephen Gutowski, Hua Chen, Chad A Brautigam, Zhe Chen, Paul C Sternweis, Xuewu Zhang

Research output: Contribution to journalArticlepeer-review

13 Scopus citations


PDZ domains are abundant protein interaction modules and typically recognize a short motif at the C terminus of their ligands, with a few residues in the motif endowing the binding specificity. The sequence-based rules, however, cannot fully account for the specificity between the vast number of PDZ domains and ligands in the cell. Plexins are transmembrane receptors that regulate processes such as axon guidance and angiogenesis. Two related guanine nucleotide exchange factors (GEFs), PDZâ€"RhoGEF and leukemiaassociated RhoGEF (LARG), use their PDZ domains to bind class B plexins and play critical roles in signaling. Here, we present the crystal structure of the full-length cytoplasmic region of PlexinB2 in complex with the PDZ domain of PDZâ€"RhoGEF. The structure reveals that, in addition to the canonical C-terminal motif/PDZ interaction, the 3D domain of PlexinB2 forms a secondary interface with the PDZ domain. Our biophysical and cell-based assays show that the secondary interface contributes to the specific interaction between plexin and PDZâ€"RhoGEF and to signaling by plexin in the cell. Formation of secondary interfaces may be a general mechanism for increasing affinity and specificity of modular domain-mediated interactions.

Original languageEnglish (US)
Pages (from-to)14852-14857
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number48
StatePublished - Dec 1 2015

ASJC Scopus subject areas

  • General


Dive into the research topics of 'Secondary PDZ domain-binding site on class B plexins enhances the affinity for PDZâ€"RhoGEF'. Together they form a unique fingerprint.

Cite this