7x14

From Proteopedia

Crystal structure of phospho-FFAT motif of MIGA2 bound to VAPB

Structural highlights

7x14 is a 2 chain structure with sequence from Mus musculoides and Mus musculus. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:	X-ray diffraction, Resolution 1.675Å
Ligands:	,
Resources:	FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

VAPB_MOUSE Endoplasmic reticulum (ER)-anchored protein that mediates the formation of contact sites between the ER and endosomes via interaction with FFAT motif-containing proteins such as STARD3 or WDR44. Interacts with STARD3 in a FFAT motif phosphorylation dependent manner. Via interaction with WDR44 participates in neosynthesized protein export. Participates in the endoplasmic reticulum unfolded protein response (UPR) by inducing ERN1/IRE1 activity. Involved in cellular calcium homeostasis regulation.[UniProtKB:O95292]

Publication Abstract from PubMed

The endoplasmic reticulum (ER)-mitochondria contact site (ERMCS) is crucial for exchanging biological molecules such as phospholipids and Ca(2+) ions between these organelles. Mitoguardin-2 (MIGA2), a mitochondrial outer membrane protein, forms the ERMCS in higher eukaryotic cells. Here, we report the crystal structures of the MIGA2 Lipid Droplet (LD) targeting domain and the ER membrane protein VAPB bound to the phosphorylated FFAT motif of MIGA2. These structures reveal that the MIGA2 LD targeting domain has a large internal hydrophobic pocket that accommodates phospholipids and that two phosphorylations of the FFAT motif are required for tight interaction of MIGA2 with VAPB, which enhances the rate of lipid transport. Further biochemical studies show that MIGA2 transports phospholipids between membranes with a strong preference for binding and trafficking phosphatidylserine (PS). These results provide a structural and molecular basis for understanding how MIGA2 mediates the formation of ERMCS and facilitates lipid trafficking at the ERMCS.

Structural basis for mitoguardin-2 mediated lipid transport at ER-mitochondrial membrane contact sites.,Kim H, Lee S, Jun Y, Lee C Nat Commun. 2022 Jun 28;13(1):3702. doi: 10.1038/s41467-022-31462-6. PMID:35764626^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

References

↑ Kim H, Lee S, Jun Y, Lee C. Structural basis for mitoguardin-2 mediated lipid transport at ER-mitochondrial membrane contact sites. Nat Commun. 2022 Jun 28;13(1):3702. doi: 10.1038/s41467-022-31462-6. PMID:35764626 doi:http://dx.doi.org/10.1038/s41467-022-31462-6