1i4a
From Proteopedia
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'''CRYSTAL STRUCTURE OF PHOSPHORYLATION-MIMICKING MUTANT T6D OF ANNEXIN IV''' | '''CRYSTAL STRUCTURE OF PHOSPHORYLATION-MIMICKING MUTANT T6D OF ANNEXIN IV''' | ||
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[[Category: Mo, Y D.]] | [[Category: Mo, Y D.]] | ||
[[Category: Seaton, B A.]] | [[Category: Seaton, B A.]] | ||
| - | [[Category: | + | [[Category: Calcium-binding]] |
| - | [[Category: | + | [[Category: Membrane-binding]] |
| - | [[Category: | + | [[Category: Phosphorylation mutant]] |
| - | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Fri May 2 19:33:19 2008'' | |
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + | |
Revision as of 16:33, 2 May 2008
CRYSTAL STRUCTURE OF PHOSPHORYLATION-MIMICKING MUTANT T6D OF ANNEXIN IV
Overview
Site-directed mutagenesis, electron microscopy, and X-ray crystallography were used to probe the structural basis of annexin IV-induced membrane aggregation and the inhibition of this property by protein kinase C phosphorylation. Site-directed mutants that either mimic (Thr6Asp, T6D) or prevent (Thr6Ala, T6A) phosphorylation of threonine 6 were produced for these studies and compared with wild-type annexin IV. In vitro assays showed that unmodified wild-type annexin IV and the T6A mutant, but not PKC-phosphorylated wild-type or the T6D mutant, promote vesicle aggregation. Electron crystallographic data of wild-type and T6D annexin IV revealed that, similar to annexin V, the annexin IV proteins form 2D trimer-based ordered arrays on phospholipid monolayers. Cryo-electron microscopic images of junctions formed between lipid vesicles in the presence of wild-type annexin IV indicated a separation distance corresponding to the thickness of two layers of membrane-bound annexin IV. In this orientation, a single layer of WT annexin IV, attached to the outer leaflet of one vesicle, would undergo face-to-face self-association with the annexin layer of a second vesicle. The 2.0-A resolution crystal structure of the T6D mutant showed that the mutation causes release of the N-terminal tail from the protein core. This change would preclude the face-to-face annexin self-association required to aggregate vesicles. The data suggest that reversible complex formation through phosphorylation and dephosphorylation could occur in vivo and play a role in the regulation of vesicle trafficking following changes in physiological states.
About this Structure
1I4A is a Single protein structure of sequence from Bos taurus. Full crystallographic information is available from OCA.
Reference
Phosphorylation mutants elucidate the mechanism of annexin IV-mediated membrane aggregation., Kaetzel MA, Mo YD, Mealy TR, Campos B, Bergsma-Schutter W, Brisson A, Dedman JR, Seaton BA, Biochemistry. 2001 Apr 3;40(13):4192-9. PMID:11300800 Page seeded by OCA on Fri May 2 19:33:19 2008
