Year: 1997
Type: article
Abstract: The annexins are characterized by their ability to bind phospholipid membranes in a Ca2+-dependent manner. Sequence variability between the N-terminal domains of the family members may contribute to the specific cellular function of each annexin. To identify proteins that interact with the N-terminal domain of synexin (annexin VII), a fusion protein was constructed composed of glutathione S-transferase fused to amino acids 1-145 of human synexin. Affinity chromatography using this construct identified sorcin as a Ca2+-dependent synexin-binding protein. Overlay assays confirmed the interaction. The glutathione S-transferase construct associates with recombinant sorcin over the range of pCa2+ = 4.7-3.1 with no binding observed at pCa2+ = 5.4. Overlay assays using deletion constructs of the synexin N-terminal domain mapped the sorcin binding site to the N-terminal 31 amino acids of the synexin protein. Additionally, synexin forms a complex with sorcin and recruits this protein to chromaffin granule membranes in a Ca2+-dependent manner. Sorcin is able to inhibit synexin-mediated chromaffin granule aggregation in a manner saturable with increasing sorcin concentrations, but does not influence the Ca2+ sensitivity of synexin-mediated granule aggregation. Therefore, the interaction between sorcin and synexin may serve to regulate the functions of these proteins on membrane surfaces in a Ca2+-dependent manner.
Source: Journal of Biological Chemistry
Authors: Amy M. Brownawell, Carl E. Creutz
Institution: University of Virginia
Language: English
Topic: S100 Proteins and Annexins
Subfield: Molecular Biology
Domain: Life Sciences
Open Access status: hybrid
Estimated APC paid: $3,430
OpenAlex ID: W1994817879