SH3b Bacterial SH3 domain homologues
SMART ACC:	SM000287
Description:	-
InterPro ACC:	IPR003646
InterPro abstract:	SH3 domains are widespread among metazoan intracellular signalling proteins and typically bind proline-rich polypeptides. This SH3 domain is a prokaryotic homologue. It might have two possible functions: (1) promoting survival of a pathogen within the invaded cell by modulating pathways controlled by SH3 domains; or (2) promoting invasion by binding to receptors on eukaryotic cells [ expand SH3 domains are widespread among metazoan intracellular signalling proteins and typically bind proline-rich polypeptides. This SH3 domain is a prokaryotic homologue. It might have two possible functions: (1) promoting survival of a pathogen within the invaded cell by modulating pathways controlled by SH3 domains; or (2) promoting invasion by binding to receptors on eukaryotic cells [ PUBMED:10322416 PUBMED:10369758 ]. SH3 (src Homology-3) domains are small protein modules containing approximately 50 amino acid residues [ PUBMED:15335710 PUBMED:11256992 ]. They are found in a great variety of intracellular or membrane-associated proteins [ PUBMED:1639195 PUBMED:14731533 PUBMED:7531822 ] for example, in a variety of proteins with enzymatic activity, in adaptor proteins, such as fodrin and yeast actin binding protein ABP-1. The SH3 domain has a characteristic fold which consists of five or six β-strands arranged as two tightly packed anti-parallel β-sheets. The linker regions may contain short helices. The surface of the SH3-domain bears a flat, hydrophobic ligand-binding pocket which consists of three shallow grooves defined by conservative aromatic residues in which the ligand adopts an extended left-handed helical arrangement. The ligand binds with low affinity but this may be enhanced by multiple interactions. The region bound by the SH3 domain is in all cases proline-rich and contains PXXP as a core-conserved binding motif. The function of the SH3 domain is not well understood but they may mediate many diverse processes such as increasing local concentration of proteins, altering their subcellular location and mediating the assembly of large multiprotein complexes [ PUBMED:7953536 ]. collapse
Family alignment:	View the Family alignment or the Alignment consensus sequence
There are 47 276 SH3b domains in 28 882 proteins in SMART's NRDB database.

Taxonomic distribution of proteins containing SH3b domains

The tree below includes only several representative species and genera. The complete taxonomic breakdown of all proteins containing SH3b domains can be accessed here. Click the counts or percentage values to display the corresponding proteins.

Predicted cellular role

Cellular role:	Signalling

Relevant references for this domain

Primary literature for the SH3b 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 SH3b domain which could be assigned to a KEGG orthologous group, and not all proteins containing SH3b 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

InterPro	IPR003646