In:
Journal of Cell Science, The Company of Biologists, Vol. 107, No. 3 ( 1994-03-01), p. 709-718
Abstract:
A Drosophila cDNA (BAD1) encoding a structural and assembly-competent homologue of the mammalian coated pit β-adaptins (β and β’ has been cloned and sequenced. In its amino-terminal region (residues 1-575), the BAD1 sequence appears intermediate between that of the mammalian β-adaptin and a predicted sequence, from cDNA 105a, which appears to code for a version of β’-adaptin. To test its functional characteristics, a ‘myc’-tagged version of BAD1 was expressed in Cos cells. The BAD1 protein was detected most clearly in plasma membrane coated pits, where it colocalized with α-adaptin, although other coated pits were noted which apparently did not contain α-adaptin. However, these are probably γ-adaptin containing pits, as BAD1 was also found colocalized with γ-adaptin in Golgi coated pits in which, typically, α-adaptin is absent. Immunoprecipitation experiments confirmed that the BAD1 protein was present in both types of adaptor complex, unlike β-adaptin which complexes with α-adaptin and β’-adaptin which partners γ-adaptin exclusively. In spite of this, BAD1 expression does not appear to mix α-adaptin and γ-adaptin distribution amongst all the coated pits: thus the location of these adaptor complexes in mammalian cells does not depend on the differences between β subunits but rather on membrane-specific interactions of other adaptor polypeptides. The differential interaction of β with α-adaptin and β’ with γ-adaptin in mammalian cells is likely to depend on the few non-conservative differences between their respective sequences and BAD1. Four of these (one with respect to β and three versus 105a) are clustered in a particular region (residues 155 to 305), which may therefore represent a domain that influences the choice of partner adaptin.
Type of Medium:
Online Resource
ISSN:
0021-9533
,
1477-9137
DOI:
10.1242/jcs.107.3.709
Language:
English
Publisher:
The Company of Biologists
Publication Date:
1994
detail.hit.zdb_id:
219171-4
detail.hit.zdb_id:
1483099-1
SSG:
12
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