Heparan sulfate chain valency controls syndecan-4 function in cell adhesion
Research output: Contribution to journal › Journal article › Research › peer-review
Fibroblasts null for the transmembrane proteoglycan, syndecan-4, have an altered actin cytoskeleton, compared to matching wild-type cells. They do not organize alpha-smooth muscle actin into bundles, but will do so when full length syndecan-4 is re-expressed. This requires the central V region of the core protein cytoplasmic domain, though not interactions with PDZ proteins. A second key requirement is multiple heparan sulfate chains. Mutant syndecan-4 with no chains, or only one chain, failed to restore the wild type phenotype, while those expressing two or three were competent. However, clustering of one-chain syndecan-4 forms with antibodies overcame the block, indicating that valency of interactions with ligands is a key component of syndecan-4 function. Measurements of focal contact/adhesion size and focal adhesion kinase phosphorylation correlated with syndecan-4 status and alpha-smooth muscle actin organization, being reduced where syndecan-4 function was compromised by a lack of multiple heparan sulfate chains.
|Journal||Journal of Biological Chemistry|
|Number of pages||12|
|Publication status||Published - 12 Feb 2010|