BAG3 promotes proliferation and migration of arterial smooth muscle cells by regulating STAT3 phosphorylation in diabetic vascular remodeling.

BACKGROUND: Diabetic vascular remodeling is the most important pathological basis of diabetic cardiovascular complications. The accumulation of advanced glycation end products (AGEs) caused by elevated blood glucose promotes the proliferation and migration of vascular smooth muscle cells (VSMCs), leading to arterial wall thickening and ultimately vascular remodeling. Therefore, the excessive proliferation and migration of VSMCs is considered as an important therapeutic target for vascular remodeling in diabetes mellitus. However, due to the lack of breakthrough in experiments, there is currently no effective treatment for the excessive proliferation and migration of VSMCs in diabetic patients. Bcl-2-associated athanogene 3 (BAG3) protein is a multifunctional protein highly expressed in skeletal muscle and myocardium. Previous research has confirmed that BAG3 can not only regulate cell survival and apoptosis, but also affect cell proliferation and migration. Since the excessive proliferation and migration of VSMCs is an important pathogenesis of vascular remodeling in diabetes, the role of BAG3 in the excessive proliferation and migration of VSMCs and its molecular mechanism deserve further investigation. METHODS: In this study, BAG3 gene was manipulated in smooth muscle to acquire SM22αCre; BAG3FL/FL mice and streptozotocin (STZ) was used to simulate diabetes. Expression of proteins and aortic thickness of mice were detected by immunofluorescence, ultrasound and hematoxylin-eosin (HE) staining. Using human aorta smooth muscle cell line (HASMC), cell viability was measured by CCK-8 and proliferation was measured by colony formation experiment. Migration was detected by transwell, scratch experiments and Phalloidin staining. Western Blot was used to detect protein expression and Co-Immunoprecipitation (Co-IP) was used to detect protein interaction. RESULTS: In diabetic vascular remodeling, AGEs could promote the interaction between BAG3 and signal transducer and activator of transcription 3 (STAT3), leading to the enhanced interaction between STAT3 and Janus kinase 2 (JAK2) and reduced interaction between STAT3 and extracellular signal-regulated kinase 1/2 (ERK1/2), resulting in accumulated p-STAT3(705) and reduced p-STAT3(727). Subsequently, the expression of matrix metallopeptidase 2 (MMP2) is upregulated, thus promoting the migration of VSMCs. CONCLUSIONS: BAG3 upregulates the expression of MMP2 by increasing p-STAT3(705) and decreasing p-STAT3(727) levels, thereby promoting vascular remodeling in diabetes. This provides a new orientation for the prevention and treatment of diabetic vascular remodeling.

Nuclear ßII-Tubulin and its Possible Utility in Cancer Diagnosis, Prognosis and Treatment.

Microtubules are organelles that usually occur only in the cytosol. Walss et al. (1999) discovered the ßII isotype of tubulin, complexed with α, in the nuclei of certain cultured cells, in non-microtubule form. When fluorescently labeled tubulins were microinjected into the cells, only αßII appeared in the nucleus, and only after one cycle of nuclear disassembly and reassembly. It appeared as if αßII does not cross the nuclear envelope but is trapped in the nucleus by the re-forming nuclear envelope in whose reassembly ßII may be involved. ßII is present in the cytoplasm and nuclei of many tumor cells. With some exceptions, normal tissues that expressed ßII rarely had ßII in their nuclei. It is possible that ßII is involved in nuclear reassembly and then disappears from the nucleus. Ruksha et al. (2019) observed that patients whose colon cancer cells in the invasive front showed no ßII had a median survival of about 5.5 years, which was more than halved if they had cytosolic ßII and further lessened if they had nuclear ßII, suggesting that the presence and location of ßII in biopsies could be a useful prognostic indicator and also that ßII may be involved in cancer progression. Yeh and Ludueña. (2004) observed that many tumors were surrounded by non-cancerous cells exhibiting cytosolic and nuclear ßII, suggesting a signaling pathway that causes ßII to be synthesized in nearby cells and localized to their nuclei. ßII could be useful in cancer diagnosis, since the presence of ßII in non-cancerous cells could indicate a nearby tumor. Investigation of this pathway might reveal novel targets for chemotherapy. Another possibility would be to combine αßII with CRISPR-Cas9. This complex would likely enter the nucleus of a cancer cell and, if guided to the appropriate gene, might destroy the cancer cell or make it less aggressive; possible targets will be discussed here. The possibilities raised here about the utility of ßII in cancer diagnosis, prognosis, biology and therapy may repay further investigation.

A method for designing the longitudinal position of a porthole in a manned submersible based on the back muscle fatigue characteristics.

OBJECTIVES: The proper porthole angle contributes to relieving the operation fatigue and improving the efficiency of oceanauts. In this study, the authors explored the effect of 3 different porthole longitudinal positions on the oceanauts' back muscles using surface electromyography (sEMG) analysis, and the characteristics of the perceived body comfort was obtained. MATERIAL AND METHODS: Overall, 40 healthy participants were recruited to perform tasks in a simulated cabin environment. Electromyographic (EMG) signals were recorded from the trapezius medius, lower trapezius, and erector spinal muscles for porthole angles of -5°, -15°, and +15°, relative to the horizontal line of sight during a 21-minute experiment. The subject comfort scores were collected at 7, 14 and 21 min. The integrated electromyogram (iEMG) and the root mean square (RMS) of EMG signals, as well as the mean power frequency (MPF), and the mean frequency (MF) were calculated. RESULTS: The subjective scores of the +15° porthole at each stage of work are higher than those of the -15° and -5° portholes. The results of iEMG, RMS, MF and MPF all indicated that the +15° porthole design was more conducive to lowering the rate of muscle fatigue, while the -5° and -15° portholes increased the muscle fatigue rate and led to greater fatigue. It was found that the lower trapezius was more prone to fatigue than the trapezius medius and erector spinal muscles. The height, weight and body mass index of the participants were found to negatively correlate with muscles at the +15° porthole, which is highly consistent with the actual situation. CONCLUSIONS: The findings suggested that the +15° position was optimal for delaying the muscle fatigue of the participants and for improving the work efficiency of oceanauts. Int J Occup Med Environ Health. 2021;34(6):701-21.

Hsa-miRNA-23a-3p promotes atherogenesis in a novel mouse model of atherosclerosis.

Of the known regulators of atherosclerosis, miRNAs have been demonstrated to play critical roles in lipoprotein homeostasis and plaque formation. Here, we generated a novel animal model of atherosclerosis by knocking in LDLRW483X in C57BL/6 mice, as the W483X mutation in LDLR is considered the most common newly identified pathogenic mutation in Chinese familial hypercholesterolemia (FH) individuals. Using the new in vivo mouse model combined with a well-established atherosclerotic in vitro human cell model, we identified a novel atherosclerosis-related miRNA, miR-23a-3p, by microarray analysis of mouse aortic tissue specimens and human aortic endothelial cells (HAECs). miR-23a-3p was consistently downregulated in both models, which was confirmed by qPCR. Bioinformatics analysis and further validation experiments revealed that the TNFα-induced protein 3 (TNFAIP3) gene was the key target of miR-23a-3p. The miR-23a-3p-related functional pathways were then analyzed in HAECs. Collectively, the present results suggest that miR-23a-3p regulates inflammatory and apoptotic pathways in atherogenesis by targeting TNFAIP3 through the NF-κB and p38/MAPK signaling pathways.

Adipose-derived stem cell-conditioned medium protects fibroblasts at different senescent degrees from UVB irradiation damages.

Adipose-derived stem cells (ADSCs) and their derivatives have aroused intense interest in fields of dermatological and aesthetic medicine. As a major component detected in ADSCs secretome, platelet-derived growth factor AA (PDGF-AA) has been reported mediating extracellular matrix deposition and remodeling, thus might contribute to its anti-aging effect. On the basis of establishing an experimental model that simulate actual skin aging by exposing HDFs to both intrinsic and extrinsic aging factors, we pretreated human dermal fibroblasts (HDFs) with ADSC-conditioned medium (ADSC-CM) before being irradiated, aiming at exploring preventive effects of ADSCs secretome against aging damages. 48 h after irradiation, we detected cellular proliferation; ß-galactosidase stain; mRNA expressions of MMP-1, MMP-9, and TIMP-1; and protein expressions of collagen I, collagen III, and elastin. Moreover, we detected related protein expression of PI3K/Akt signal pathway, which can be activated by PDGF-AA and was newly found to promote extracellular matrix protein synthesis. Concentration of PDGF-AA in the prepared ADSC-CM decreased over time and maintained excellent bioactivity at low temperature until the 11th week. ADSC-CM pretreatment can slightly or significantly improve cellular proliferative activity and reduce cellular senescence in irradiated HDFs. Besides, ADSC-CM pretreatment increased collagen I, collagen III, elastin, and TIMP-1 expressions but decreased MMP-1 and MMP-9 expressions both in irradiated and nonirradiated HDFs. ADSC-CM pretreatment significantly increased pAkt protein expression, and ECM protein expression greatly decreased in case of LY294002 application. The results were similar in three generations of HDFs, yet varied with different degrees. Generally, ADSC-CM we prepared demonstrates a certain degree of positive role in preventing HDFs from intrinsic and extrinsic aging damages and that PDGF-AA may contribute to making it become effective with some other components in ADSC-CM.

Systematic prediction of familial hypercholesterolemia caused by low-density lipoprotein receptor missense mutations.

BACKGROUND AND AIMS: Familial hypercholesterolemia (FH) is a an autosomal dominant disorder characterized by very high levels of low-density lipoprotein cholesterol (LDL-C). It is estimated that >85% of all FH-causing mutations involve genetic variants in the LDL receptor (LDLR). To date, 795 single amino acid LDLR missense mutations have been reported in the Leiden Open Variation Database (LOVD). However, the functional impact of these variants on the LDLR pathway has received little attention and remains poorly understood. We aim to establish a systematic functional prediction model for LDLR single missense mutations. METHODS: Using a combined structural modeling and bioinformatics algorithm, we developed an in silico prediction model called "Structure-based Functional Impact Prediction for Mutation Identification" (SFIP-MutID) for FH with LDLR single missense mutations. We compared the pathogenicity and functional impact predictions of our model to those of other conventional tools with experimentally validated variants, as well as in vitro functional test results for patients with LDLR variants. RESULTS: Our SFIP-MutID model systematically predicted 13,167 potential LDLR single amino acid missense substitutions with biological effects. The functional impact of 52 out of 54 specific mutations with reported in vitro experimental data was predicted correctly. Further functional tests on LDLR variants from patients were also consistent with the prediction of our model. CONCLUSIONS: Our LDLR structure-based computational model predicted the pathogenicity of LDLR missense mutations by linking genotypes with LDLR functional phenotypes. Our model complements other prediction tools for variant interpretation and facilitates the precision diagnosis and treatment of FH and atherosclerotic cardiovascular diseases.

A high-density genetic map of extra-long staple cotton (Gossypium barbadense) constructed using genotyping-by-sequencing based single nucleotide polymorphic markers and identification of fiber traits-related QTL in a recombinant inbred line population.

BACKGROUND: Gossypium barbadense (Sea Island, Egyptian or Pima cotton) cotton has high fiber quality, however, few studies have investigated the genetic basis of its traits using molecular markers. Genome complexity reduction approaches such as genotyping-by-sequencing have been utilized to develop abundant markers for the construction of high-density genetic maps to locate quantitative trait loci (QTLs). RESULTS: The Chinese G. barbadense cultivar 5917 and American Pima S-7 were used to develop a recombinant inbred line (RIL) population with 143 lines. The 143 RILs together with their parents were tested in three replicated field tests for lint yield traits (boll weight and lint percentage) and fiber quality traits (fiber length, fiber elongation, fiber strength, fiber uniformity and micronaire) and then genotyped using GBS to develop single-nucleotide polymorphism (SNP) markers. A high-density genetic map with 26 linkage groups (LGs) was constructed using 3557 GBS SNPs spanning a total genetic distance of 3076.23 cM at an average density of 1.09 cM between adjacent markers. A total of 42 QTLs were identified, including 24 QTLs on 12 LGs for fiber quality and 18 QTLs on 7 LGs for lint yield traits, with LG1 (9 QTLs), LG10 (7 QTLs) and LG14 (6 QTLs) carrying more QTLs. Common QTLs for the same traits and overlapping QTLs for different traits were detected. Each individual QTLs explained 0.97 to 20.7% of the phenotypic variation. CONCLUSIONS: This study represents one of the first genetic mapping studies on the fiber quality and lint yield traits in a RIL population of G. barbadense using GBS-SNPs. The results provide important information for the subsequent fine mapping of QTLs and the prediction of candidate genes towards map-based cloning and marker-assisted selection in cotton.

Identification of CD24 as a marker for tumorigenesis of melanoma.

OBJECTIVE: Cutaneous melanoma (CM) is a common skin cancer. Surgery is still the primary treatment for CM, as melanoma is resistant to chemotherapy. In the recent years, it has been found that cancer stem-like cells (CSCs) are responsible for this drug resistance. CD24 is a widely used marker to isolate CSCs. In this study, we aimed to analyze the properties of CD24+ and CD24- subpopulation of melanoma cells. MATERIALS AND METHODS: We isolated CD24+ cells CSCs using magnetic-activated cell sorting system. We extracted total RNA and carried out reverse transcription polymerase chain reaction analysis. We counted the cell colonies using soft agar assay and assessed the cell invasion using cell migration assay. We implanted CD24+ or CD24- cells into the flank of non-obese diabetic severe combined immunodeficiency mice, and measured the tumor volumes every 5 days until the end of the experiment. We carried out immunohistochemical analysis to study the tissue sections. RESULTS: We demonstrated that the CD24+ subpopulation has self-renewal properties in vitro and in vivo by using soft agar assay and xenograft tumor model. Furthermore, we confirmed that CD24 expression is accompanied by activation of Notch1 signaling pathway. CONCLUSION: This study provides new knowledge on the role of CD24 in the tumorigenic ability of melanoma.

Interactions of ß tubulin isotypes with glutathione in differentiated neuroblastoma cells subject to oxidative stress.

Microtubules are a major component of the neuronal cytoskeleton. Tubulin, the subunit protein of microtubules, is an α/ß heterodimer. Both α and ß exist as families of isotypes, whose members are encoded by different genes and have different amino acid sequences. The ßII and ßIII isotypes are very prominent in the nervous system. Our previous work has suggested that ßII may play a role in neuronal differentiation, but the role of ßIII in neurons is not well understood. In the work reported here, we examined the roles of the different ß-tubulin isotypes in response to glutamate/glycine treatment, and found that both ßII and ßIII bind to glutathione in the presence of ROS, especially ßIII. In contrast, ßI did not bind to glutathione. Our results suggest that ßII and ßIII, but especially ßIII, may play an important role in the response of neuronal cells to stress. In view of the high levels of ßII and ßIII expressed in the nervous system it is conceivable that these tubulin isotypes may use their sulfhydryl groups to scavenge ROS and protect neuronal cells against oxidative stress.

Promoting potential of adipose derived stem cells on peripheral nerve regeneration.

The ultimate goal of treating peripheral nerve defects is reconstructing continuity of the nerve stumps to regain nerve conduction and functional recovery. Clinically, autologous nerve grafts and Schwann cell (SC) therapy have limitations, such as the need for secondary surgery, sacrifice of another nerve and donor site complication. Adipose derived stem cells (ADSCs) may promise to be ideal alternative cells of SCs. To explore the potential of ADSCs promoting peripheral nerve regeneration, the present study investigated the influences of ADSCs on proliferation and neurotrophic function of SCs using co­culture model in vitro. Western blot analysis, immunocytochemistry, a cell viability assay, reverse transcription­polymerase chain reaction (RT­PCR) and ELISA were applied for examining the interaction of ADSCs and SCs in a co­culture model in vitro. Western blot analysis and immunocytochemistry demonstrated that protein expression levels of glial filament acidic protein (GFAP) and S100 in ADSCs co­cultured with SCs for 14 days were significantly higher compared with cells cultured alone. Cell viability assay indicated that the cell viability of SCs co­cultured with ADSCs for 3, 4, 5, 6 and 7 days was significantly higher than those cultured alone. RT­PCR showed that expression levels of neurotrophic factors [nerve growth factor (NGF) and glial cell line­derived neurotrophic factor (GDNF)] and extracellular matrix components [fibronectin (FN) and laminin (LN)] in SCs co­cultured with ADSCs for 14 days were significantly higher than those in SCs cultured alone. NGF, GDNF, FN and LN in the supernatants of co­culture system were significantly higher than cells cultured alone, as ELISA revealed. The results of this study suggested that the transplantation of ADSCs may have a promoting potential to the peripheral nerve regeneration as undifferentiated state.

Adipose­derived stem cells and hyaluronic acid based gel compatibility, studied in vitro.

Minimally invasive aesthetic and cosmetic procedures have increased in popularity. Injectable dermal fillers provide soft tissue augmentation, improve facial rejuvenation and wrinkles, and correct tissue defects. To investigate the use of adipose­derived stem cells integrated with a hyaluronic acid based gel as a dermal filler, the present study used cytotoxicity studies, proliferation studies, adipogenic and osteogenic differentiation, apoptosis assays and scanning electron microscopy. Although hyaluronic acid induced low levels of apoptosis in adipose­derived stem cells, its significantly promoted proliferation of adipose­derived stem cells. Hyaluronic acid demonstrates little toxicity against adipose­derived stem cells. Adipose­derived stem cells were able to differentiate into adipocytes and osteoblasts. Furthermore, scanning electron microscopy revealed that adipose­derived stem cells maintained intact structures on the surface of hyaluronic acid as well as in it, and demonstrated abundant cell attachments. The present study demonstrated the compatibility of adipose­derived stem cells and hyaluronic acid based gels in vitro.

Synchronous correction of lip and nasal deformity in complete bilateral cleft lip / 中华整形外科杂志

<p><b>OBJECTIVE</b>To investigate the technique and its therapeutic effect of synchronous correction of lip and nasal deformity in complete bilateral cleft lip.</p><p><b>METHODS</b>29 patients with complete bilateral cleft lip underwent synchronous correction of lip and nasal deformity with the modified Mulliken method for Asians. The philtral flap was 6-7 mm in length, and 3-4 mm in width at the collumellar-labial junction. The distance between the peaks of cupid's bow was 4-5 mm. The bilateral edge of philtral flap was de-epithelialized and advanced to form philtrum column. The lateral lip was advanced to the medial site, and the central vermilion tubercle was constructed with the bilateral vermilion-mucosal flap. Through the alar rim incision, the displaced cartilage was dissected and repositioned to raise the nasal tip. The follow-up period was 6 months to 6 years.</p><p><b>RESULTS</b>Satisfactory results were achieved in all patients. The reconstructed upper lip had invisible scar with natural philtrum and column. The vermilion had good appearance with tubercle. The length of nasal column was not decreased and depression of nasal tip and alar was greatly improved.</p><p><b>CONCLUSIONS</b>Our modified Mulliken method is effective in synchronous correction of lip and nasal deformity in bilateral cleft lip.</p>

Distinct roles of different fragments of PDCD4 in regulating the metastatic behavior of B16 melanoma cells.

Melanoma is an aggressive cutaneous malignancy. In this study, we demonstrated that the levels of the programmed cell death 4 (PDCD4) protein and mRNA were lower in tumor tissues compared with normal tissues. In order to further investigate the effects of PDCD4 and its fragments in B16 melanoma cells, we established B16 clones with expression of different PDCD4 fragments. Intact PDCD4, PDCD4∆164­469 and PDCD4∆327-440 expression, respectively, decreased proliferation and migration and increased apoptosis in B16 cells in vitro. We found that intact PDCD4, PDCD4∆164-469 or PDCD4∆327-440 can inhibit the activity of MMP-2 and the expression of CXCR4. However, PDCD4∆164-275 showed no effects on B16 cells. These results may prove helpful for the development of novel therapies for melanoma treatment.

Endogenous PGE(2) induces MCP-1 expression via EP4/p38 MAPK signaling in melanoma.

It has been demonstrated that cyclooxygenase-2 (COX-2) is expressed in melanoma tissues and prostaglandin E(2) (PGE(2)) is produced by melanoma cells in vitro. However, the roles of COX-2/PGE(2) in melanoma are largely unknown. In the present study, we set out to analyze the correlation of endogenous PGE(2) with the expression of macrophage chemoattractant protein-1 (MCP-1) and to identify the signaling pathway involved. It was found that MCP-1 mRNA was heterogeneously expressed in 18 melanoma tissue specimens, and the levels of MCP-1 mRNA were positively correlated with those of COX-2 mRNA. Inhibition of endogenous PGE(2) production by a COX-2 inhibitor, COX-2 siRNA or an NFκB inhibitor suppressed MCP-1 expression, whereas treatment with TNF-α (to stimulate endogenous PGE(2) production) or exogenous PGE(2) enhanced MCP-1 expression in melanoma cells. Both the EP4 antagonist and the p38 MAPK inhibitor reduced MCP-1 production in melanoma cells, and abrogated the increased MCP-1 secretion induced by TNF-α or exogenous PGE(2). Conditioned medium from melanoma cells promoted macrophage migration, which was blocked by inhibitors of the PGE(2)/EP4/p38 MAPK signaling pathway. These results indicate that endogenous PGE(2) induces MCP-1 expression via EP4/p38 MAPK signaling in an autocrinal manner in melanoma, and melanoma cell-derived PGE(2) may be involved in macrophage recruitment in the melanoma microenvironment.

The distribution of ß-tubulin isotypes in cultured neurons from embryonic, newborn, and adult mouse brains.

Tubulin, the subunit protein of microtubules, is an α/ß heterodimer. Both α- and ß-tubulin exist as numerous isotypes, differing in their amino acid sequences and encoded by different genes. The differences are highly conserved in evolution, suggesting that they are functionally significant. Neurons are a potentially very useful system for elucidating this significance, because they are highly differentiated cells and rich in tubulin isotypes. We have examined the distribution of ß-tubulin isotypes in mouse primary cultured cortical neurons from embryonic fetus, newborn pups and adults. Neurons from both embryonic and adult mouse brains express the ßI, ßII, and ßIII isotypes, but apparently not ßIV or ßV. ßI, ßII, and ßIII are found in both cell bodies and neurites. However, the situation is different in newborn mice. Although ßI and ßIII are present in these neurons in both cell bodies and neurites and ßIV is absent, just like in embryonic and adult mice, two striking differences were noted in the neurons from newborn mice. First, ßV is apparently present evanescently in the neurons in both cell bodies and neurites. Interestingly, the ßV was expressed strongly in newborn neurons after one day of culture; expression became much weaker after 3days, and almost disappeared after 5days. Second, the distribution of ßII is different from other isotypes. After newborn mouse neurons were cultured for 3days, ßII started to disappear partly from the cell bodies; this was much more pronounced after five days in culture. Our findings suggest that ßII's major function may involve the neurites and not the cell body. They also raise the possibility that ßV has a unique role in the neurons of newborn mice.

[One-staged correction of lip and nose deformities in complete unilateral cleft lip].

OBJECTIVE: To investigate the influence of timing, operative method and perioperative sequence treatment on the therapeutic effect of one-staged correction of lip and nose deformities in complete unilateral cleft lip. METHODS: Seventy-six patients with unilateral complete cleft lip, aged from 3 to 12 months, underwent one-staged correction of lip and nose deformities, based on the Salyer, Noordhoff method. Sequence treatment was performed before and after operation. RESULTS: The patients were followed up for 3 months to 20 years with excellent results in 39 cases (51.3%), good in 33 patients (43.4%), unsatisfied in 4 patients (5.3%). CONCLUSIONS: Good results can be achieved when the one-staged correction of lip and nose deformities, combined with perioperative sequence treatment, is performed. The operative technique of plastic surgeon or maxillofacial surgeon is also important for less morbidity and scar.

The beta isotypes of tubulin in neuronal differentiation.

The differences among the vertebrate beta isotypes of tubulin are highly conserved in evolution, suggesting that they have functional significance. To address this, we have used differentiating neuroblastoma cells as a model system. These cells express the betaI, betaII, and betaIII isotypes. Although there is no difference prior to differentiation, a striking difference is seen after differentiation. Both betaI and betaIII occur in cell bodies and neurites, while betaII occurs mostly in neurites. Knocking down betaI causes a large decrease in cell viability while silencing betaII and betaIII does not. Knocking down betaII causes a large decrease in neurite outgrowth without affecting viability. Knocking down betaIII has little effect on neurite outgrowth and only decreases viability if cells are treated with glutamate and glycine, a combination known to generate free radicals and reactive oxygen species. It appears, therefore, that betaI is required for cell viability, betaII for neurite outgrowth and betaIII for protection against free radicals and reactive oxygen species.

A high efficiency strategy for binding property characterization of peptide-binding domains.

A large proportion of protein-protein interactions is mediated by families of peptide-binding domains. Comprehensive characterization of each of these domains is critical for understanding the mechanisms and networks of protein interaction at the domain level. However, existing methods are all based on large scale screenings for each domain that are inefficient to deal with hundreds of members in major domain families. We developed a systematic strategy for efficient binding property characterization of peptide-binding domains based on high throughput validation screening of a specialized candidate ligand library using yeast two-hybrid mating array. Its outstanding feature is that the overall efficiency is dramatically improved compared with that of traditional screening, and it will be higher as the system cycles. PDZ domain family was first used to test the strategy. Five PDZ domains were rapidly characterized. Broader binding properties were identified compared with other methods, including novel recognition specificities that provided the basis for major revision of conventional PDZ classification. Several novel interactions were discovered, serving as significant clues for further functional investigation. This strategy can be easily extended to a variety of peptide-binding domains as a powerful tool for comprehensive analysis of domain binding property in proteomic scale.