Testis-specific human small heat shock protein HSPB9 is a cancer/testis antigen, and potentially interacts with the dynein subunit TCTEL1.
Searching EST databases for new members of the human small heat shock protein family, we recently identified HSPB9, which is expressed exclusively in testis as determined by Northern blotting (Kappé et al., Biochim. Biophys. Acta 1520, 1-6, 2001). Here we confirm this testis-specific expression pattern by RT-PCR in a larger series of normal tissues. Interestingly, while screening HSPB9 ESTs, we also noted expression in tumours, which could be verified by RT-PCR. Protein expression of HSPB9 was also detected in normal human testis and various tumour samples using immunohistochemical staining. We thus conclude that HSPB9 belongs to the steadily growing number of cancer/testis antigens. To get a better understanding of the function of HSPB9, we performed a yeast two-hybrid screen to search for HSPB9-interacting proteins. TCTEL1, a light chain component of cytoplasmic and flagellar dynein, interacted in both the yeast two-hybrid system and in immunoprecipitation experiments with HSPB9. Additionally, immunohistochemical staining showed co-expression of HSPB9 and TCTEL1 in similar stages of spermatogenesis and in tumour cells. The possible functional significance of this interaction is discussed.
de Wit
Nicole J W
NJ
Department of Pathology, University Medical Centre Nijmegen, 6500 HB Nijmegen, The Netherlands.
Verschuure
Pauline
P
Kappé
Guido
G
King
Stephen M
SM
de Jong
Wilfried W
WW
van Muijen
Goos N P
GN
Boelens
Wilbert C
WC
D014408:Biomarkers, Tumor / Q000096:biosynthesis*; D002277:Carcinoma / Q000235:genetics / Q000378:metabolism*; D045744:Cell Line, Tumor; D003001:Cloning, Molecular; D004398:Dyneins / Q000235:genetics / Q000378:metabolism*; D006360:Heat-Shock Proteins; D006801:Humans; D008297:Male; D008545:Melanoma / Q000235:genetics / Q000378:metabolism*; D008869:Microtubule-Associated Proteins / Q000235:genetics / Q000378:metabolism*; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding / Q000235:genetics; D017346:Protein Serine-Threonine Kinases / Q000096:biosynthesis* / Q000235:genetics; D012333:RNA, Messenger / Q000096:biosynthesis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013736:Testicular Neoplasms / Q000235:genetics / Q000378:metabolism*; D020798:Two-Hybrid System Techniques; D056427:t-Complex Genome Region
D014408:Biomarkers, Tumor; C533376:DYNLT1 protein, human; C433765:HSPB9 protein, human; D006360:Heat-Shock Proteins; D008869:Microtubule-Associated Proteins; D009687:Nuclear Proteins; D012333:RNA, Messenger; D017346:Protein Serine-Threonine Kinases; D004398:Dyneins