TY - JOUR
T1 - Effects of phosphorylation on the structure and backbone dynamics of the intrinsically disordered connexin43 C-terminal domain
AU - Grosely, Rosslyn
AU - Kopanic, Jennifer L.
AU - Nabors, Sarah
AU - Kieken, Fabien
AU - Spagnol, Gaëlle
AU - Al-Mugotir, Mona
AU - Zach, Sydney
AU - Sorgen, Paul L.
PY - 2013/8/23
Y1 - 2013/8/23
N2 - Background: Phosphorylation of the connexin43 C-terminal (Cx43CT) domain regulates gap junction intercellular communication (GJIC). Results: Phosphorylation alters the α-helical propensity of the Cx43CT. Conclusion: Altering the conformational preference of the Cx43CT presents a novel mechanism for regulation of GJIC. Significance: Cx43CT residues susceptible to structural alterations are prime targets for chemical modulators of GJIC. Phosphorylation of the connexin43 C-terminal (Cx43CT) domain regulates gap junction intercellular communication. However, an understanding of the mechanisms by which phosphorylation exerts its effects is lacking. Here, we test the hypothesis that phosphorylation regulates Cx43 gap junction intercellular communication by mediating structural changes in the C-terminal domain. Circular dichroism and nuclear magnetic resonance were used to characterize the effects of phosphorylation on the secondary structure and backbone dynamics of soluble and membrane-tethered Cx43CT domains. Cx43CT phospho-mimetic isoforms, which have Asp substitutions at specific Ser/Tyr sites, revealed phosphorylation alters the α-helical content of the Cx43CT domain only when attached to the membrane. The changes in secondary structure are due to variations in the conformational preference and backbone flexibility of residues adjacent and distal to the site(s) of modification. In addition to the known direct effects of phosphorylation on molecular partner interactions, the data presented here suggest phosphorylation may also indirectly regulate binding affinity by altering the conformational preference of the Cx43CT domain.
AB - Background: Phosphorylation of the connexin43 C-terminal (Cx43CT) domain regulates gap junction intercellular communication (GJIC). Results: Phosphorylation alters the α-helical propensity of the Cx43CT. Conclusion: Altering the conformational preference of the Cx43CT presents a novel mechanism for regulation of GJIC. Significance: Cx43CT residues susceptible to structural alterations are prime targets for chemical modulators of GJIC. Phosphorylation of the connexin43 C-terminal (Cx43CT) domain regulates gap junction intercellular communication. However, an understanding of the mechanisms by which phosphorylation exerts its effects is lacking. Here, we test the hypothesis that phosphorylation regulates Cx43 gap junction intercellular communication by mediating structural changes in the C-terminal domain. Circular dichroism and nuclear magnetic resonance were used to characterize the effects of phosphorylation on the secondary structure and backbone dynamics of soluble and membrane-tethered Cx43CT domains. Cx43CT phospho-mimetic isoforms, which have Asp substitutions at specific Ser/Tyr sites, revealed phosphorylation alters the α-helical content of the Cx43CT domain only when attached to the membrane. The changes in secondary structure are due to variations in the conformational preference and backbone flexibility of residues adjacent and distal to the site(s) of modification. In addition to the known direct effects of phosphorylation on molecular partner interactions, the data presented here suggest phosphorylation may also indirectly regulate binding affinity by altering the conformational preference of the Cx43CT domain.
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U2 - 10.1074/jbc.M113.454389
DO - 10.1074/jbc.M113.454389
M3 - Article
C2 - 23828237
AN - SCOPUS:84883161814
SN - 0021-9258
VL - 288
SP - 24857
EP - 24870
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
IS - 34
ER -