DUF1944
SMART ACC:	SM001170
Description:	Members of this family adopt a structure consisting of several large open beta-sheets. Their exact function has not, as yet, been determined [(PUBMED:12135361)].
InterPro ACC:	IPR015258
InterPro abstract:	This entry represents the β-sheet shell domain found in vitellinogen, which generally corresponds to the lipovitellin-2 peptide product. This domain consists of several large open β-sheets [ PUBMED:12135361 ]. It is often found C-terminal to IPR001747 … expand This entry represents the β-sheet shell domain found in vitellinogen, which generally corresponds to the lipovitellin-2 peptide product. This domain consists of several large open β-sheets [ PUBMED:12135361 ]. It is often found C-terminal to IPR001747 and IPR015255. Vitellinogen precursors provide the major egg yolk proteins that are a source of nutrients during early development of oviparous vertebrates and invertebrates. Vitellinogen precursors are multi-domain apolipoproteins that are cleaved into distinct yolk proteins. Different vitellinogen precursors exist, which are composed of variable combinations of yolk protein components; however, the cleavage sites are conserved [ PUBMED:17314313 PUBMED:9692232 ]. In vertebrates, a complete vitellinogen is composed of an N-terminal signal peptide for export, followed by four regions that can be cleaved into yolk proteins: lipovitellin-1, phosvitin, lipovitellin-2, and a von Willebrand factor type D domain (YGP40). Vitellinogens are post-translationally glycosylated and phosphorylated in the endoplasmic reticulum and Golgi complex of hepatocytes, before being secreted into the circulatory system to be taken up by oocytes. In the ovary, vitellinogens bind to specific Vtgr receptors on oocyte membranes to become internalised by endocytosis, where they are cleaved into yolk proteins by cathepsin D. YGP40 is released into the yolk plasma before or during compartmentation of lipovitellin-phosvitin complex into the yolk granule. The different yolk proteins have distinct roles. Phosvitins are important in sequestering calcium, iron and other cations for the developing embryo. Phosvitins are one of the most phosphorylated (10%) proteins in nature, the high concentration of phosphate groups providing efficient metal-binding sites in clusters [ PUBMED:17189915 PUBMED:8838584 ]. Lipovitellins are involved in lipid and metal storage, and contain a heterogeneous mixture of about 16% (w/w) noncovalently bound lipid, most being phospholipid. Lipovitellin-1 contains two chains, LV1N and LV1C [ PUBMED:12135361 PUBMED:9687371 ]. collapse
GO process:	lipid transport (GO:0006869)
GO function:	lipid transporter activity (GO:0005319)
Family alignment:	View the Family alignment or the Alignment consensus sequence
There are 546 DUF1944 domains in 539 proteins in SMART's NRDB database.

Taxonomic distribution of proteins containing DUF1944 domains

The tree below includes only several representative species and genera. The complete taxonomic breakdown of all proteins containing DUF1944 domains can be accessed here. Click the counts or percentage values to display the corresponding proteins.

Relevant references for this domain

Primary literature for the DUF1944 domain is listed below. Automatically-derived, secondary literature is also available.

KEGG pathways involving proteins which contain this domain

This information is based on the mapping of SMART genomic protein database to KEGG orthologous groups. Percentages are related to the number of proteins containing a DUF1944 domain which could be assigned to a KEGG orthologous group, and not all proteins containing DUF1944 domains. Please note that proteins can be included in multiple pathways, ie. the numbers below will not add to 100%.

KEGG pathways

Some of these pathways are included in the interactive Pathways Explorer overview maps. Select an overview map and click the button below to highlight them in iPath.

KEGG orthologous groups

Some of these KOs are included in the interactive Pathways Explorer overview maps. Select an overview map and click the button below to highlight them in iPath.

3D structures in PDB containing this domain

Links to other resources describing this domain

Pfam	DUF1944
InterPro	IPR015258