Identification and characterization of novel clathrin adaptor-related proteins.
We have identified a human approximately 87-kDa protein, designated as gamma2-adaptin, that is similar to gamma-adaptin (called gamma1-adaptin in this paper), a large chain of the AP-1 clathrin-associated adaptor complex, not only in the primary structure (60% amino acid identity) but also in the domain organization. Northern blot analysis has shown that its mRNA is expressed in a variety of tissues. Analysis using a yeast two-hybrid system has revealed that, similarly to gamma1-adaptin, gamma2-adaptin is capable of interacting not only with the sigma1 chain (called as sigma1A in this paper), the small chain of the AP-1 complex, but also with a novel sigma1-like protein, designated as sigma1B, which shows an 87% amino acid identity to sigma1A; and that, unlike gamma1-adaptin, it is unable to interact with beta1-adaptin, another large chain of the AP-1 complex. Immunofluorescence microscopy analysis has revealed that gamma2-adaptin is localized to paranuclear vesicular structures that are not superimposed on structures containing gamma1-adaptin. Furthermore, unlike gamma1-adaptin, gamma2-adaptin is recruited onto membranes in the presence of a fungal antibiotic, brefeldin A. These data suggest that gamma2-adaptin constitute a novel adaptor-related complex that participates in a transport step different from that of AP-1.
Takatsu
H
H
Institute of Biological Sciences, University of Tsukuba, Tsukuba Science City, Ibaraki 305-8572, Japan.
Sakurai
M
M
Shin
H W
HW
Murakami
K
K
Nakayama
K
K
D033961:Adaptor Protein Complex 1; D033962:Adaptor Protein Complex 2; D033965:Adaptor Protein Complex alpha Subunits; D033982:Adaptor Protein Complex gamma Subunits; D034002:Adaptor Protein Complex sigma Subunits; D033942:Adaptor Proteins, Vesicular Transport; D000595:Amino Acid Sequence; D001483:Base Sequence; D001665:Binding Sites; D002460:Cell Line; D002966:Clathrin / Q000737:chemistry; D003001:Cloning, Molecular; D017931:DNA Primers; D006801:Humans; D008565:Membrane Proteins / Q000096:biosynthesis* / Q000737:chemistry; D008969:Molecular Sequence Data; D009928:Organ Specificity; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000737:chemistry; D012441:Saccharomyces cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D018808:Transcription Factor AP-1 / Q000737:chemistry / Q000378:metabolism*; D014158:Transcription, Genetic; D014162:Transfection; D014407:Tumor Cells, Cultured
C438983:AP1S1 protein, human; C510065:AP2S1 protein, human; C499068:APS1 protein, S cerevisiae; D033961:Adaptor Protein Complex 1; D033962:Adaptor Protein Complex 2; D033965:Adaptor Protein Complex alpha Subunits; D033982:Adaptor Protein Complex gamma Subunits; D034002:Adaptor Protein Complex sigma Subunits; D033942:Adaptor Proteins, Vesicular Transport; D002966:Clathrin; D017931:DNA Primers; D008565:Membrane Proteins; D012333:RNA, Messenger; D011994:Recombinant Proteins; D029701:Saccharomyces cerevisiae Proteins; D018808:Transcription Factor AP-1; C499071:adaptor protein complex 1, sigma 1 subunit