Interaction of prostate specific membrane antigen with clathrin and the adaptor protein complex-2.
Prostate-specific membrane antigen (PSMA) is an integral membrane glycoprotein expressed in prostatic epithelia and is being evaluated as a therapeutic target in prostate cancer. It undergoes constitutive receptor-mediated endocytosis via clathrin-coated pits, which is enhanced in the presence of monoclonal antibodies directed against it. We describe distinct interactions of PSMA with clathrin and the clathrin adaptor protein-2 (AP-2) complex, two components of clathrin-coated pits. The intracellular N-terminal domain of PSMA interacts with the N-terminal globular domain of clathrin heavy chain. Deletion analysis revealed an important determinant of this interaction residing within the proximal portion of the clathrin heavy chain N-terminal domain (amino acids 1-85) distinct from the clathrin binding sites of other known clathrin-binding proteins. Furthermore, PSMA interacts with the ear domain of alpha-adaptin (an AP-2 subunit), and a glutamic acid residue at position 7 in the cytoplasmic tail of PSMA is essential for this interaction. These data indicate that PSMA exhibits a high affinity, specific association with the clathrin-based endocytic machinery by distinct interactions with both clathrin and AP-2. Thus, although PSMA is a new member of the dual AP and clathrin binding proteins, its alpha-adaptin and clathrin heavy chain binding determinants are distinct from those of other members.
Goodman
Oscar B
OB
Urologic Oncology Research Laboratory, Department of Urology, Weill Medical College of Cornell University-New York Presbyterian Hospital, New York, NY, USA.
Barwe
Sonali P
SP
Ritter
Brigitte
B
McPherson
Peter S
PS
Vasko
Ann-Jeanette
AJ
Keen
James H
JH
Nanus
David M
DM
Bander
Neil H
NH
Rajasekaran
Ayyappan K
AK
D033962:Adaptor Protein Complex 2 / Q000737:chemistry / Q000502:physiology*; D000818:Animals; D000954:Antigens, Surface / Q000737:chemistry / Q000502:physiology*; D001665:Binding Sites; D002460:Cell Line; D002966:Clathrin / Q000737:chemistry / Q000502:physiology*; D022163:Clathrin-Coated Vesicles / Q000502:physiology; D004285:Dogs; D004705:Endocytosis; D043425:Glutamate Carboxypeptidase II / Q000737:chemistry / Q000502:physiology*; D008297:Male; D051379:Mice
D033962:Adaptor Protein Complex 2; D000954:Antigens, Surface; D002966:Clathrin; C473848:FOLH1 protein, human; D043425:Glutamate Carboxypeptidase II