PROSITE documentation PDOC00761
Clathrin adaptor complexes medium chain signatures


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 medium chains of AP-1 and AP-2 are evolutionary related proteins of about 50 Kd. Homologs of AP47 and AP50 have also been found in Caenorhabditis elegans (genes unc-101 and ap50) [2] and yeast (gene APM1 or YAP54) [3].

Some more divergent, but clearly evolutionary related proteins have also been found in yeast: APM2 and YBR288c.

As signature patterns, we selected two conserved regions, one located in the N-terminal region, the other from the central section of these proteins.

Last update:

December 2004 / Pattern and text revised.


Technical section

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

CLAT_ADAPTOR_M_1, PS00990; Clathrin adaptor complexes medium chain signature 1  (PATTERN)

CLAT_ADAPTOR_M_2, PS00991; Clathrin adaptor complexes medium chain signature 2  (PATTERN)


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

2AuthorsLee J. Jongeward G.D. Sternberg P.W.
Titleunc-101, a gene required for many aspects of Caenorhabditis elegans development and behavior, encodes a clathrin-associated protein.
SourceGenes Dev. 8:60-73(1994).
PubMed ID8288128

3AuthorsNakayama Y. Goebl M. O'Brine G.B. Lemmon S. Pingchang C.E. Kirchhausen T.
SourceEur. J. Biochem. 202:569-574(1991).

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