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Adaptor proteins are proteins which are accessory to main proteins in a signal transduction pathway. These proteins tend to lack any intrinsic enzymatic activity themselves but instead mediate specific protein-protein interactions that drive the formation of protein complexes. Examples of adaptor proteins include MyD88, Grb2 and SHC1.

[edit] Signalling components

Much of the specificity of signal transduction depends on the recruitment of several signalling components such as protein kinases and G-protein GTPases into short lived active complexes in response to an activating signal such as a growth factor binding to its receptor.

[edit] Domains

Adaptor proteins usually contain several domains within their structure (e.g., Src homology 2 (SH2) and SH3 domains) which allow specific interactions with several other specific proteins. SH2 domains recognise specific amino acid sequences within proteins containing phosphotyrosine residues and SH3 domains recognise proline-rich sequences within specific peptide sequence contexts of proteins.

There are many other types of interaction domains found within adaptor and other signalling proteins which allow a rich diversity of specific and coordinated protein-protein interactions to occur within the cell during signal transduction.

[edit] Genes

Genes encoding adaptor proteins include:

• GRAP - GRB2-related adaptor protein
• GRAP2 - GRB2-related adaptor protein 2
• LDLRAP1 - low density lipoprotein receptor adaptor protein 1
• NCK1 - NCK adaptor protein 1
• NCK2 - NCK adaptor protein 2
• NOS1AP - nitric oxide synthase 1 (neuronal) adaptor protein
• PIK3AP1 - phosphoinositide-3-kinase adaptor protein 1
• SH2B1 - SH2B adaptor protein 1
• SH2B2 - SH2B adaptor protein 2
• SH2B3 - SH2B adaptor protein 3
• SHB - Src homology 2 domain containing adaptor protein B
• SLC4A1AP - solute carrier family 4 (anion exchanger), member 1, adaptor protein
• GAB2, GRB2-associated binding protein 2

[edit] See also

• Wikipedia:MeSH_D12.776#MeSH_D12.776.157.057_---_adaptor_proteins.2C_signal_transducing
• Wikipedia:MeSH_D12.776#MeSH_D12.776.543.990.150_---_adaptor_proteins.2C_vesicular_transport

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