PROSITE documentation PDOC00761 [for PROSITE entry PS00991]

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_2, PS00991; Clathrin adaptor complexes medium chain signature 2  (PATTERN)

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