Human alpha spectrin II and the Fanconi anemia proteins FANCA and FANCC interact to form a nuclear complex.
Fanconi anemia (FA) is a genetic disorder characterized by bone marrow failure, congenital abnormalities, cancer susceptibility, and a marked cellular hypersensitivity to DNA interstrand cross-linking agents, which correlates with a defect in ability to repair this type of damage. We have previously identified an approximately 230-kDa protein present in a nuclear protein complex in normal human lymphoblastoid cells that is involved in repair of DNA interstrand cross-links and shows reduced levels in FA-A cell nuclei. The FANCA gene appears to play a role in the stability or expression of this protein. We now show that p230 is a well known structural protein, human alpha spectrin II (alphaSpIISigma*), and that levels of alphaSpIISigma* are not only significantly reduced in FA-A cells but also in FA-B, FA-C and FA-D cells (i.e. in all FA cell lines tested), suggesting a role for these FA proteins in the stability or expression of alphaSpIISigma*. These studies also show that alphaSpIISigma* forms a complex in the nucleus with the FANCA and FANCC proteins. alphaSpIISigma* may thus act as a scaffold to align or enhance interactions between FA proteins and proteins involved in DNA repair. These results suggest that FA represents a disorder in which there is a deficiency in alphaSpIISigma*.
McMahon
L W
LW
Department of Pathology, University of Medicine and Dentistry-New Jersey Medical School, Newark, New Jersey 07103, USA.
Walsh
C E
CE
Lambert
M W
MW
D015153:Blotting, Western; D018797:Cell Cycle Proteins; D002460:Cell Line; D004260:DNA Repair; D004268:DNA-Binding Proteins; D005199:Fanconi Anemia / Q000235:genetics*; D052217:Fanconi Anemia Complementation Group A Protein; D052218:Fanconi Anemia Complementation Group C Protein; D051856:Fanconi Anemia Complementation Group Proteins; D006367:HeLa Cells; D006801:Humans; D009687:Nuclear Proteins / Q000378:metabolism; D010455:Peptides / Q000737:chemistry* / Q000172:deficiency; D011233:Precipitin Tests; D011485:Protein Binding; D011506:Proteins / Q000378:metabolism*; D013049:Spectrin / Q000172:deficiency / Q000378:metabolism*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; C498471:FANCA protein, human; C497651:FANCC protein, human; D052217:Fanconi Anemia Complementation Group A Protein; D052218:Fanconi Anemia Complementation Group C Protein; D051856:Fanconi Anemia Complementation Group Proteins; D009687:Nuclear Proteins; D010455:Peptides; D011506:Proteins; C042459:p 230; D013049:Spectrin