Proteins, proteomics

adaptor protein

An adaptor protein links components in signaling pathways by acting as an accessory to the chief proteins in a signal transduction pathway.

adaptor genes : adaptor proteins : AP-1, AP-2 : Cbl : clathrin : Grb2 : LIME : Nck : RING : SH2, SH3 : thymocyte development : TIR : TLR : Toll-like receptor : ubiquitin-ligases

Adaptor proteins lack intrinsic enzymatic activity, instead they mediate specific protein-protein interactions that drive the formation of protein complexes. The specificity of Toll-like receptor signaling occurs by means of adaptor proteins possessing Toll–interleukin 1 receptor (TIR) domains.

Examples of adaptor proteins include:
Adaptor protein complex 1 (AP-1) and AP-2, which interact with clathrin-coated vesicles located at the trans-Golgi network (TGN) or the plasma membrane. Heterotetramer adaptor protein complexes that function as vesicle coat components and cargo molecule selectors in various membrane trafficking pathways.

Cbl adaptor proteins are RING-type E3 ubiquitin ligases that may be involved in the negative regulation of thymocyte development, targeting its substrate for ubiquitination [ 1 ]. The ubiquitin ligase activity of Cbl, and of its homologue Cbl-b, plays a role in the negative regulation of upstream kinases, such as Lck, Syk and PI3K, in T and B cells

LIME (Lck-interacting molecule) is a raft-associated adaptor protein that is expressed predominantly in T lymphocytes, and which becomes tyrosine phosphorylated after cross-linking of the CD4 or CD8 coreceptors. Phospho-LIME associates with the Src family kinase Lck and its negative regulator, Csk.

Src homology = Shc proteins → SH2 recognize phosphotyrosine residues and SH3 domains recognise proline-rich sequences

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


Labels: , , , , , , ,

. . . since 11/21/06