PROSITE documentation PDOC00760
Clathrin adaptor complexes small chain signature


Clathrin coated vesicles (CCV) mediate intracellular membrane traffic such as receptor mediated endocytosis. In addition to clathrin, the CCV are composed of a number of other components including oligomeric complexes which are known as adaptor or clathrin assembly proteins (AP) complexes [1]. The adaptor complexes are believed to interact with the cytoplasmic tails of membrane proteins, leading to their selection and concentration. In mammals two type of adaptor complexes are known: AP-1 which is associated with the Golgi complex and AP-2 which is associated with the plasma membrane. Both AP-1 and AP-2 are heterotetramers that consist of two large chains - the adaptins - (γ and β' in AP-1; α and β in AP-2); a medium chain (AP47 in AP-1; AP50 in AP-2) and a small chain (AP19 in AP-1; AP17 in AP-2).

The small chains of AP-1 and AP-2 are evolutionary related proteins of about 18 Kd. Homologs of AP17 and AP19 have also been found in yeast (genes APS1/ YAP19 and APS2/YAP17) [2,3,4]. AP17 and AP19 are also related to the zeta-chain [5] of coatomer (zeta-cop), a cytosolic protein complex that reversibly associates with Golgi membranes to form vesicles that mediate biosynthetic protein transport from the endoplasmic reticulum, via the Golgi up to the trans Golgi network.

As a signature pattern, we selected a conserved region in the central section of these proteins.

Last update:

December 2001 / Pattern and text revised.


Technical section

PROSITE method (with tools and information) covered by this documentation:

CLAT_ADAPTOR_S, PS00989; Clathrin adaptor complexes small chain signature  (PATTERN)


1AuthorsPearse B.M. Robinson M.S.
TitleClathrin, adaptors, and sorting.
SourceAnnu. Rev. Cell Biol. 6:151-171(1990).
PubMed ID2177341

2AuthorsKirchhausen T. Davis A.C. Frucht S. O'Brine Greco B. Payne G.S. Tubb B.
TitleAP17 and AP19, the mammalian small chains of the clathrin-associated protein complexes show homology to Yap17p, their putative homolog in yeast.
SourceJ. Biol. Chem. 266:11153-11157(1991).
PubMed ID2040623

3AuthorsNakai M. Takada T. Endo T.
TitleCloning of the YAP19 gene encoding a putative yeast homolog of AP19, the mammalian small chain of the clathrin-assembly proteins.
SourceBiochim. Biophys. Acta 1174:282-284(1993).
PubMed ID8373805

4AuthorsPhan H.L. Finlay J.A. Chu D.S. Tan P.K. Kirchhausen T. Payne G.S.
TitleThe Saccharomyces cerevisiae APS1 gene encodes a homolog of the small subunit of the mammalian clathrin AP-1 complex: evidence for functional interaction with clathrin at the Golgi complex.
SourceEMBO J. 13:1706-1717(1994).
PubMed ID8157009

5AuthorsKuge O. Hara-Kuge S. Orci L. Ravazzola M. Amherdt M. Tanigawa G. Wieland F.T. Rothman J.E.
Titlezeta-COP, a subunit of coatomer, is required for COP-coated vesicle assembly.
SourceJ. Cell Biol. 123:1727-1734(1993).
PubMed ID8276893

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