Download MendeleyA conformational switch in the Piccolo C2A domain regulated by alternative splicing.
Garcia, J., Gerber, S.H., Sugita, S., Sudhof, T.C., Rizo, J.(2004) Nat Struct Mol Biol 11: 45-53
- PubMed: 14718922
- DOI: https://doi.org/10.1038/nsmb707
- Primary Citation of Related Structures:
1RH8 - PubMed Abstract:
C2 domains are widespread Ca2+-binding modules. The active zone protein Piccolo (also known as Aczonin) contains an unusual C2A domain that exhibits a low affinity for Ca2+, a Ca2+-induced conformational change and Ca2+-dependent dimerization. We show here that removal of a nine-residue sequence by alternative splicing increases the Ca2+ affinity, abolishes the conformational change and abrogates dimerization of the Piccolo C2A domain. The NMR structure of the Ca2+-free long variant provides a structural basis for these different properties of the two splice forms, showing that the nine-residue sequence forms a beta-strand otherwise occupied by a nonspliced sequence. Consequently, Ca2+-binding to the long Piccolo C2A domain requires a marked rearrangement of secondary structure that cannot occur for the short variant. These results reveal a novel mechanism of action of C2 domains and uncover a structural principle that may underlie the alteration of protein function by short alternatively spliced sequences.
Organizational Affiliation:
Department of Biochemistry and Pharmacology, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, Texas 75390, USA.
