Abstract
A self-association reaction involving the plasma membrane-associated clathrin assembly protein AP-2 has been detected by incubating AP-2 alone under solution conditions that would favor the assembly of complete coat structures if clathrin were present. Self-association was rapid, unaffected by nonionic detergents, readily reversible, and gave rise to sedimentable aggregates. Only the AP subtype AP-2 exhibited self-association: the structurally or functionally related assembly proteins AP-1 and AP-3 and unrelated proteins neither self-associated nor were incorporated into the AP-2 aggregate. AP-2 interactions responsible for self-association were of high affinity, with an apparent Kd of approximately 10-8 M. By proteolytic dissection, the self-association domain was localized to the core of the molecule containing the intact 50- and 16-kDa polypeptides in association with the truncated 60-66-kDa moieties of the parent α/β polypeptides. Self-association of the intact AP-2 molecule was pH-dependent, exhibiting an apparent pKa ≈ 7.4. While it is unlikely that the large AP-2 aggregates formed in solution are themselves biologically relevant structures, the AP-2 interactions involved in their formation have properties consistent with their occurrence in intact cells and thus may be important in cellular functions of the plasma membrane-localized assembly protein.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 4437-4441 |
| Number of pages | 5 |
| Journal | Journal of Biological Chemistry |
| Volume | 266 |
| Issue number | 7 |
| State | Published - Mar 5 1991 |
| Externally published | Yes |
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ASJC Scopus subject areas
- Biochemistry
Cite this
Self-association of the plasma membrane-associated clathrin assembly protein AP-2. / Beck, Kenneth A; Keen, James H.
In: Journal of Biological Chemistry, Vol. 266, No. 7, 05.03.1991, p. 4437-4441.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Self-association of the plasma membrane-associated clathrin assembly protein AP-2
AU - Beck, Kenneth A
AU - Keen, James H.
PY - 1991/3/5
Y1 - 1991/3/5
N2 - A self-association reaction involving the plasma membrane-associated clathrin assembly protein AP-2 has been detected by incubating AP-2 alone under solution conditions that would favor the assembly of complete coat structures if clathrin were present. Self-association was rapid, unaffected by nonionic detergents, readily reversible, and gave rise to sedimentable aggregates. Only the AP subtype AP-2 exhibited self-association: the structurally or functionally related assembly proteins AP-1 and AP-3 and unrelated proteins neither self-associated nor were incorporated into the AP-2 aggregate. AP-2 interactions responsible for self-association were of high affinity, with an apparent Kd of approximately 10-8 M. By proteolytic dissection, the self-association domain was localized to the core of the molecule containing the intact 50- and 16-kDa polypeptides in association with the truncated 60-66-kDa moieties of the parent α/β polypeptides. Self-association of the intact AP-2 molecule was pH-dependent, exhibiting an apparent pKa ≈ 7.4. While it is unlikely that the large AP-2 aggregates formed in solution are themselves biologically relevant structures, the AP-2 interactions involved in their formation have properties consistent with their occurrence in intact cells and thus may be important in cellular functions of the plasma membrane-localized assembly protein.
AB - A self-association reaction involving the plasma membrane-associated clathrin assembly protein AP-2 has been detected by incubating AP-2 alone under solution conditions that would favor the assembly of complete coat structures if clathrin were present. Self-association was rapid, unaffected by nonionic detergents, readily reversible, and gave rise to sedimentable aggregates. Only the AP subtype AP-2 exhibited self-association: the structurally or functionally related assembly proteins AP-1 and AP-3 and unrelated proteins neither self-associated nor were incorporated into the AP-2 aggregate. AP-2 interactions responsible for self-association were of high affinity, with an apparent Kd of approximately 10-8 M. By proteolytic dissection, the self-association domain was localized to the core of the molecule containing the intact 50- and 16-kDa polypeptides in association with the truncated 60-66-kDa moieties of the parent α/β polypeptides. Self-association of the intact AP-2 molecule was pH-dependent, exhibiting an apparent pKa ≈ 7.4. While it is unlikely that the large AP-2 aggregates formed in solution are themselves biologically relevant structures, the AP-2 interactions involved in their formation have properties consistent with their occurrence in intact cells and thus may be important in cellular functions of the plasma membrane-localized assembly protein.
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M3 - Article
VL - 266
SP - 4437
EP - 4441
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
SN - 0021-9258
IS - 7
ER -