Domain

Zinc finger, Sec23/Sec24-type (IPR006895)

Short name: Znf_Sec23_Sec24

Domain relationships

None.

Description

Zinc finger (Znf) domains are relatively small protein motifs which contain multiple finger-like protrusions that make tandem contacts with their target molecule. Some of these domains bind zinc, but many do not; instead binding other metals such as iron, or no metal at all. For example, some family members form salt bridges to stabilise the finger-like folds. They were first identified as a DNA-binding motif in transcription factor TFIIIA from Xenopus laevis (African clawed frog), however they are now recognised to bind DNA, RNA, protein and/or lipid substrates [PMID: 10529348, PMID: 15963892, PMID: 15718139, PMID: 17210253, PMID: 12665246]. Their binding properties depend on the amino acid sequence of the finger domains and of the linker between fingers, as well as on the higher-order structures and the number of fingers. Znf domains are often found in clusters, where fingers can have different binding specificities. There are many superfamilies of Znf motifs, varying in both sequence and structure. They display considerable versatility in binding modes, even between members of the same class (e.g. some bind DNA, others protein), suggesting that Znf motifs are stable scaffolds that have evolved specialised functions. For example, Znf-containing proteins function in gene transcription, translation, mRNA trafficking, cytoskeleton organisation, epithelial development, cell adhesion, protein folding, chromatin remodelling and zinc sensing, to name but a few [PMID: 11179890]. Zinc-binding motifs are stable structures, and they rarely undergo conformational changes upon binding their target.

COPII (coat protein complex II)-coated vesicles carry proteins from the endoplasmic reticulum (ER) to the Golgi complex [PMID: 11535824]. COPII-coated vesicles form on the ER by the stepwise recruitment of three cytosolic components: Sar1-GTP to initiate coat formation, Sec23/24 heterodimer to select SNARE and cargo molecules, and Sec13/31 to induce coat polymerisation and membrane deformation [PMID: 12239560].

Sec23 p and Sec24p are structurally related, folding into five distinct domains: a beta-barrel, a zinc-finger, an alpha/beta trunk domain (IPR006896), an all-helical region (IPR006900), and a C-terminal gelsolin-like domain (IPR007123). This entry describes an approximately 55-residue Sec23/24 zinc-binding domain, which lies against the beta-barrel at the periphery of the complex.

GO terms

Biological Process

GO:0006888 ER to Golgi vesicle-mediated transport
GO:0006886 intracellular protein transport

Molecular Function

GO:0008270 zinc ion binding

Cellular Component

GO:0030127 COPII vesicle coat

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.
Pfam
SUPERFAMILY