Family

Transferrin family (IPR001156)

Short name: Transferrin_fam

Family relationships

  • Transferrin family (IPR001156)

Description

Transferrins are eukaryotic iron-binding glycoproteins that control the level of free iron in biological fluids [PMID: 3032619]. The proteins have arisen by duplication of a domain, each duplicated domain binding one iron atom. Members of the family include blood serotransferrin (siderophilin); milk lactotransferrin (lactoferrin); egg white ovotransferrin (conalbumin); and membrane-associated melanotransferrin.

Additional members of this family include inhibitor of carbonic anhydrase (ICA; mammals), major yolk protein (sea urchins), saxiphilin (frog), pacifastin (crayfish), and TTF-1 (algae). Most family members contain two transferrin-like domains of around 340 amino acids, the result of an ancient duplication event [PMID: 15621505]. Each of the duplicated domains can be further divided into two subdomains that form a cleft inside of which the iron atom is bound in iron-transporting transferrin [PMID: 2585506]. The iron-coordinating residues consist of an aspartic acid, two tyrosines and a histidine, as well as an arginine that coordinates a requisite anion. In addition to iron and anion liganding residues, the transferrin-like domain contains conserved cysteine residues involved in disulphide bond formation.

Human lactoferrin is a serine peptidase belonging to MEROPS peptidase family S60, clan SR. It is found at high concentrations in all human secretions, where it plays a major role in mucosal defence. Lactoferrin cleaves IgA1 protease at an arginine-rich region defined by amino acids RRSRRSVR and digests Hap at a similar arginine-rich sequence (VRSRRAAR). Ser259 and Lys73 form a catalytic dyad, reminiscent of a number of bacterial serine proteases.

GO terms

Biological Process

GO:0006879 cellular iron ion homeostasis
GO:0006826 iron ion transport

Molecular Function

GO:0008199 ferric iron binding

Cellular Component

GO:0005576 extracellular region

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.
PROSITE profiles
SMART
Pfam
PRINTS