Human kinesin superfamily member 4 is dominantly localized in the nuclear matrix and is associated with chromosomes during mitosis.
In a previous study, we identified the human counterpart of murine kinesin superfamily member 4 (KIF4), a microtubule-based motor protein [Oh, Hahn, Torrey, Shin, Choi, Lee, Morse and Kim (2000) Biochim. Biophys. Acta 1493, 219-224]. As an initial step to understand the function(s) of human KIF4, its subcellular localization in HeLa cells was examined by using immunocytochemical and subcellular fractionation methods, and it was found that most KIF4 is localized in the nucleus. Since murine KIF4 is known to transport cytoplasmic vesicles, dominant nuclear localization of the human counterpart was somewhat surprising. Subsequent subnuclear fractionation revealed predominant association of KIF4 with the nuclear matrix. These results clearly indicate that human KIF4 is, at least, a nuclear protein. In further confirmation of this conclusion, the hexapeptide PKLRRR (amino acids 773-778) in the molecule was found to function as a nuclear localization signal. During the mitotic phase of the cell cycle, human KIF4 was associated with the chromosomes, suggesting that human KIF4 might be a microtubule-based mitotic motor, with DNA as its cargo.
Lee
Y M
YM
Institute for Medical Sciences, School of Medicine, Ajou University, Suwon 442-749, South Korea.
Lee
S
S
Lee
E
E
Shin
H
H
Hahn
H
H
Choi
W
W
Kim
W
W
D000230:Adenocarcinoma; D000595:Amino Acid Sequence; D006528:Carcinoma, Hepatocellular; D002467:Cell Nucleus / Q000502:physiology*; D002877:Chromosomes, Human / Q000502:physiology*; D017931:DNA Primers; D005260:Female; D006801:Humans; D016547:Kinesins / Q000235:genetics / Q000378:metabolism*; D008113:Liver Neoplasms; D008297:Male; D008938:Mitosis / Q000502:physiology*; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D011471:Prostatic Neoplasms; D016415:Sequence Alignment; D017384:Sequence Deletion; D017386:Sequence Homology, Amino Acid; D014407:Tumor Cells, Cultured; D002583:Uterine Cervical Neoplasms
D017931:DNA Primers; D009687:Nuclear Proteins; C484228:KIF4A protein, human; C484229:KIF4B protein, human; D016547:Kinesins