GHB Glycoprotein hormone beta chain homologues.
SMART ACC:	SM000068
Description:	Also called gonadotropins. Glycoprotein hormones consist of two glycosylated chains (alpha and beta) of similar topology.
InterPro ACC:	IPR001545
InterPro abstract:	The crystal structures of four growth factors; nerve growth factor, transforming growth factor-beta, platelet-derived growth factor, and human chorionic gonadotropin from four separate superfamilies revealed that these proteins are structurally related and share a common overall topology [ PUBMED:8490958 ]. These proteins … expand The crystal structures of four growth factors; nerve growth factor, transforming growth factor-beta, platelet-derived growth factor, and human chorionic gonadotropin from four separate superfamilies revealed that these proteins are structurally related and share a common overall topology [ PUBMED:8490958 ]. These proteins show very little sequence homology, but they all have an unusual arrangement of six cysteines linked to form a "cystine-knot" conformation. The active forms of these proteins are dimers, either homo- or heterodimers [ PUBMED:7663117 ]. Because of their shape, there appears to be an intrinsic requirement for the cystine-knot growth factors to form dimers. This extra level of organisation increases the variety of structures built around this simple structural motif [ PUBMED:7583638 ]. Glycoprotein hormones [ PUBMED:6267989 PUBMED:1445230 ] (or gonadotropins) are a family of proteins which include the mammalian hormones follitropin (FSH), lutropin (LSH), thyrotropin (TSH) and chorionic gonadotropin (CG), as well as at least two forms of fish gonadotropins. All these hormones consist of two glycosylated chains (alpha and beta). In mammalian gonadotropins, the alpha chain is identical in the four types of hormones but the beta chains, while homologous, are different. The beta chains are proteins of about 100 to 140 amino acid residues which contain the cysteine-knot domain [ PUBMED:8202136 ], as shown in the following schematic representation. +----------------------+ \| +------------\|-----------------------------+ \| +-\|------------\|--------+ \| \| \| \| \| \| \| xxxCxxxxxxxCxCxxCxCxxxxxxxCxxxxxxxxCxxxxxxxCxCxCxxCxxxxxCxxxxxxxxxxx \| \| \| \| \| \| \| \| \| \| +--+ +-\|------------------------+ \| +--------------------------+'C': conserved cysteine involved in a disulphide bond. collapse
GO component:	extracellular region (GO:0005576)
GO function:	hormone activity (GO:0005179)
Family alignment:	View the Family alignment or the Alignment consensus sequence
There are 1 683 GHB domains in 1 681 proteins in SMART's NRDB database.

Taxonomic distribution of proteins containing GHB domains

The tree below includes only several representative species and genera. The complete taxonomic breakdown of all proteins containing GHB 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 GHB domain is listed below. Automatically-derived, secondary literature is also available.

Disease genes where sequence variants are found in this domain

UniRef sequences and OMIM curated human diseases associated with missense mutations within the GHB domain.

Protein	Description	Disease / phenotype
LSHB_HUMAN		OMIM:152780 : Hypogonadism, hypergonadotropic ; ?Male pseudohermaphroditism due to defective LH

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 GHB domain which could be assigned to a KEGG orthologous group, and not all proteins containing GHB 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	Cys_knot
PROSITE	GHB_DOMAIN
InterPro	IPR001545