Rabbit Anti-Human MYCBP Polyclonal antibody

The secondary structure analyses of proteins hold immense importance in the field of protein science because it plays a vital role in its hierarchical classification. It is the most important transitional step in the prediction of the three-dimensional structure of any protein. The aim of the current study is to quantitatively determine the secondary structure of an important ciliary protein, viz, an MYC-binding protein-1 (MYCBP-1) orthologue, viz, flagellar-associated protein 174 (FAP174) from the green alga, Chlamydomonas reinhardtii. FAP174 binds to A-kinase anchoring protein 240 (AKAP240) and has a crucial role to play in ciliary motility. Hence, the biochemical characterization of FAP174 becomes more vital in understanding its molecular function. The accurate secondary structure of FAP174 was investigated through circular dichroism (CD) and Fourier transform infrared spectroscopy (FTIR) combined with partial least square regression (PLSR) methods. The far-UV CD spectrum of FAP174 exhibited a positive band at 192 nm and negative bands at 208 and 221 nm, whereas quantification through BeStSel web server revealed 65% alpha-helix, approximately 2% of antiparallel beta-sheets, 6% of beta-turns, and 27% of unordered structures. These results were further confirmed by FTIR spectrum of FAP174 that revealed amide I and II bands at 1654 and 1547 cm(-1), respectively. And the PLSR calibration models led to the quantification of the secondary structure for FAP174 protein that fairly corroborated with the values obtained by quantifying CD spectrum, these being approximately 54% alpha-helix, 0% beta-sheets, approximately 12% beta-turns, and approximately 34% other structures. The recombinant FAP174 protein is therefore considerably alpha-helical and has negligible or no beta-sheets.

BackgroundTriple-negative breast cancer (TNBC) is an aggressive breast cancer subtype that lacks effective therapeutic targets. Sperm-associated antigen 5 (SPAG5) is a mitotic spindle-associated protein that is involved in various biological processes in cervical cancer and bladder urothelial carcinoma. However, the role of SPAG5 in TNBC remains undefined.MethodsThe expression of SPAG5 was examined in TNBC patients via quantitative real-time polymerase chain reaction (qRT-PCR), western blotting, and immunohistochemistry (IHC). The biological functions of SPAG5 in TNBC and the underlying mechanisms were investigated in vitro and in vivo.ResultsSPAG5 expression was significantly upregulated in TNBC tissues compared with that in paired adjacent noncancerous tissues (ANTs). High SPAG5 expression was associated with increased lymph node metastasis and high risk of local recurrence. SPAG5 protein expression was significantly associated with poor disease-free survival in TNBC. Gene set enrichment analysis of TNBC data from The Cancer Genome Atlas (TCGA) indicated that high SPAG5 expression was significantly associated with cell cycle and the ATR-BRCA pathway. Functional assays demonstrated that SPAG5 expression promoted tumor growth in vitro and in vivo. In addition, SPAG5-silenced cells were more sensitive to the PARP inhibitor (PARPi) olaparib. Mechanistically, SPAG5 interacted with c-MYC binding protein (MYCBP), thereby increasing MYCBP protein levels and leading to increased c-MYC transcriptional activity, which promoted the expression of the c-MYC target genes: CDC20, CDC25C, BRCA1, BRCA2, and RAD51.Knockdown of MYCBP or c-MYC abolished the SPAG5-induced cell-cycle progression and cell proliferation of TNBC.ConclusionsCollectively, our results indict that SPAG5 is an efficient prognostic factor in TNBC, and that SPAG5 knockdown increases the sensitivity of TNBC to the PARPi olaparib. SPAG5 promotes tumor growth and DNA repair by increasing c-MYC transcriptional activity via interaction with MYCBP. The SPAG5/MYCBP/c-MYC axis may represent a potential therapeutic target for TNBC treatment.