Focal adhesion kinase regulates the phosphorylation protein tyrosine phosphatase-α at Tyr789 in breast cancer cells.

Protein tyrosine phosphatase (PTP)­α regulates the phosphorylation of focal adhesion kinase (FAK), which is important in cellular signal transduction and integration of proteins. It has been demonstrated that a FAK­Del33 mutation (deletion of exon 33; KF437463) in breast cancer tissues regulates cell migration through FAK/Src signaling activation. However, the detailed pathway for Src activation with FAK­Del33 remains to be elucidated. The present study used a retroviral expression system to examine changes in PTPα phosphorylation affected by the FAK­Del33 protein in breast cancer cells. Small interfering (si)RNA targeting PTPα interfered with the phosphorylation of Src. Wound­healing and migration assays were performed to identify cell morphology and quantitative analysis was performed by examining band color depth in western blot analysis. Significant differences were observed in the phosphorylation level of PTPα at Tyr789 between the FAK­Del33 and the wild­type breast cancer cells, suggesting that FAK regulated the phosphorylation level of PTPα at Tyr789 in breast cancer mutant FAK­Del33 cells. The gene expression profile with FAK siRNA did not alter the levels of phosphorylation in other mutants, including autophosphorylation disability (Y397F), ATP kinase dominant negative (K454R) and protein 4.1, ezrin, radixin, moesin domain attenuate (Δ375). FAK RNAi inhibited the activity of the FAK­Del33 at the Src site and rescued the elevated cell migration and invasion. The present study demonstrated for the first time, to the best of our knowledge, an increase in the phosphorylation level of PTPα­Tyr789 by its upstream activator, FAK­Del33, leading to Src activation in certain breast cancer cells, which has significant implications for metastatic potential.

Somatic mutational analysis of FAK in breast cancer: a novel gain-of-function mutation due to deletion of exon 33.

Focal adhesion kinase (FAK) regulates cell adhesion, migration, proliferation, and survival. We identified a novel splicing mutant, FAK-Del33 (exon 33 deletion, KF437463), in both breast and thyroid cancers through colony sequencing. Considering the low proportion of mutant transcripts in samples, this mutation was detected by TaqMan-MGB probes based qPCR. In total, three in 21 paired breast tissues were identified with the FAK-Del33 mutation, and no mutations were found in the corresponding normal tissues. When introduced into a breast cell line through lentivirus infection, FAK-Del33 regulated cell motility and migration based on a wound healing assay. We demonstrated that the expression of Tyr397 (main auto-phosphorylation of FAK) was strongly increased in FAK-Del33 overexpressed breast tumor cells compared to wild-type following FAK/Src RTK signaling activation. These results suggest a novel and unique role of the FAK-Del33 mutation in FAK/Src signaling in breast cancer with significant implications for metastatic potential.

[Soybean allergens and hypoallergenic germplasm enhancement].

Food allergy is a public sanitary problem which has received attention worldwide. It is becoming an increasingly interesting problem to decrease the concentration of allergens for improvement of the food security. Soybean allergens in seeds are composing of storage proteins, structure proteins, and disease-related proteins. Among them, Gly m Bd 28K, Gly m Bd 30K and Gly m Bd 60K are the major allergens located in 7S conglycinin fragments. By recognizing allergens' physicochemical property, hypersensitivity and gene structure, certain progresses had been made to reduce the concentration of allergens in soybean through food processing, traditional breeding and genetic engineering. The paper reviewed the sorts and characters of soybean allergens, the physicochemical property of the three immunodominant allergens and their gene structures. Progress in developing hypoallergenic cultivars was also discussed.