The serine/threonine p21-activated kinases (PAKs), as main effectors of the Rho GTPases Cdc42 and Rac, represent a group of important molecular switches linking the complex cytoskeletal networks to broad neural activity. PAKs show wide expression in the brain, but they differ in specific cell types, brain regions, and developmental stages. PAKs play an essential and differential role in controlling neural cytoskeletal remodeling and are related to the development and fate of neurons as well as the structural and functional plasticity of dendritic spines. PAK-mediated actin signaling and interacting functional networks represent a common pathway frequently affected in multiple neurodevelopmental and neurodegenerative disorders. Considering specific small-molecule agonists and inhibitors for PAKs have been developed in cancer treatment, comprehensive knowledge about the role of PAKs in neural cytoskeletal remodeling will promote our understanding of the complex mechanisms underlying neurological diseases, which may also represent potential therapeutic targets of these diseases.
Animals ; Cytoskeleton/genetics* ; Humans ; Nervous System Diseases/genetics* ; Neurons/enzymology* ; Signal Transduction ; p21-Activated Kinases/metabolism*

OBJECTIVE: To investigate the clinical phenotype and genetic basis of a child with epilepsy and global developmental delay. METHODS: A child with epilepsy and global developmental delay who had visited West China Second University Hospital, Sichuan University on April 1, 2021 was selected as the study subject. Clinical data of the child were reviewed. Genomic DNA was extracted from peripheral blood samples of the child and his parents. Whole exome sequencing (WES) was carried out for the child, and candidate variant was verified by Sanger sequencing and bioinformatic analysis. A literature review was also carried out by searching databases such as Wanfang data knowledge service platform, China National Knowledge Infrastructure, PubMed, ClinVar and Embase to summarize the clinical phenotypes and genotypes of the affected children. RESULTS: The child was a 2-year-and-2-month-old male with epilepsy, global developmental delay and macrocephaly. Results of WES showed that the child has harbored a c.1427T>C variant of the PAK1 gene. Sanger sequencing confirmed that neither of his parents has carried the same variant. Only one similar case had been recorded by the dbSNP, OMIM, HGMD, and ClinVar databases. No frequency for this variant among Asian population was available in the ExAC, 1000 Genomes, and gnomAD databases. Prediction with IFT, PolyPhen-2, LRT, Mutation Taster, and FATHMM online software suggested that this variant is deleterious to the function of encoded protein. Based on the Standards and Guidelines for the Interpretation of Sequence Variants: A Joint Consensus Recommendation of the American College of Medical Genetics and Genomics (ACMG), the PAK1 gene c.1427T>C variant was determined to be likely pathogenic. CONCLUSION The PAK1 gene c.1427T>C variant probably underlay the epilepsy and global developmental delay in this child, which has provided a reference for the clinical diagnosis and genetic counseling in children with similar disorders.
Humans ; Male ; China ; Computational Biology ; Consensus ; Epilepsy/genetics* ; Genotype ; Mutation ; p21-Activated Kinases/genetics* ; Child, Preschool

Animals ; Gene Expression ; Mice ; Mice, Inbred Strains ; Spinal Cord ; metabolism ; Spinal Cord Injuries ; genetics ; metabolism ; p21-Activated Kinases ; genetics

OBJECTIVE: To explore the genetic etiology for a child with profound intellectual disabilities and obvious behavioral abnormalities. METHODS: A male child who had presented at the Zhongnan Hospital of Wuhan University on December 2, 2020 was selected as the study subject. Peripheral blood samples of the child and his parents were collected and subjected to whole exome sequencing (WES). Candidate variant was verified by Sanger sequencing. Short tandem repeat (STR) analysis was carried out to determine its parental origin. The splicing variant was also validated in vitro with a minigene assay. RESULTS: WES results revealed that the child had harbored a novel splicing variant of c.176-2A>G in the PAK3 gene, which was inherited from his mother. The results of minigene assay have confirmed aberrant splicing of exon 2. According to the guidelines from the American College of Medical Genetics and Genomics, it was classified as a pathogenic variant (PVS1+PM2_Supporting+PP3). CONCLUSION The novel splicing variant c.176-2A>G of the PAK3 gene probably underlay the disorder in this child. Above finding has expanded the variation spectrum of the PAK3 gene and provided a basis for genetic counseling and prenatal diagnosis for this family.
Child ; Female ; Humans ; Male ; Pregnancy ; Exons ; Intellectual Disability/genetics* ; Mothers ; Mutation ; p21-Activated Kinases/genetics* ; Parents ; RNA Splicing

OBJECTIVETo observe the effect of p21-activated kinase-1 (PAK1) gene transfection on the invasiveness of human colorectal carcinoma SW480 cells in vitro.

METHODSSW480 cells in routine culture were transfected with the recombinant plasmid EGFP-C1/PAK1 via Lipofectamine(TM) 2000. The expression of PAK1 protein in SW480 cells was detected using Western blotting, and the changes of the invasiveness of SW480 cells were evaluated using Boyden chamber invasion assay.

RESULTSForty-eight hours after transfection with pEGFP-C1/ PAK1, the PAK1 protein expression increased significantly in comparison with those in negative and vector control groups. The invasiveness of the SW480 cells was significantly enhanced after the transfection.

CONCLUSIONThe PAK1 gene transfection can increase the expression of PAK1 in SW480 cells and enhance the invasiveness of the cells. PAK1 can be associated with the invasiveness and metastasis of colorectal carcinoma cells.

Cell Line, Tumor ; Colorectal Neoplasms ; genetics ; pathology ; Gene Expression ; Genetic Vectors ; Humans ; Neoplasm Invasiveness ; Neoplasm Metastasis ; Plasmids ; Transfection ; p21-Activated Kinases ; genetics

OBJECTIVETo investigate the clinicopathological value of the expression and amplification of P21-activated kinase 1 gene (PAK1) in colorectal carcinoma(CRC).

METHODSImmunohistochemistry (IHC), fluorescence in situ hybridization (FISH) and terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling(TUNEL) methods were used to examine the protein expression, amplification of PAK1 and cell apoptosis in 80 cases of CRC and 30 cases of colorectal adenoma by tissue microarray.

RESULTSIHC showed an overexpression of PAK1 protein in 26% of colorectal adenomas and 62% of CRCs. Significant association was found between expression of PAK1 and tumor histological grade as well as tumor clinical stage(P<0.05). In poor-differentiated(G(3)) CRCs, PAK1 expression in 90% carcinoma was up-regulated, which was significantly higher than that in tumors of G(1/2)(51%). Overexpression of PAK1 was detected in 78% of CRCs in later clinical stages (Dukes C, D), which was significantly higher than that in early clinical stages (Dukes A,B, 53%). In addition, negative correlation between PAK1 overexpression and cell apoptosis was observed in these CRC cohorts(P<0.05). FISH revealed that amplification of PAK1 gene was examined in only 3% CRCs.

CONCLUSIONSOverexpression of PAK1 protein may play an important role in development and progression of colorectal neoplasms and it is closely associated with the malignant histological and invasive phenotype of CRCs. The expression of PAK1 in CRC may be used as one of the new molecular markers in predicting tumors malignant potential and progression.

Apoptosis ; Colorectal Neoplasms ; genetics ; pathology ; Female ; Gene Expression ; Gene Expression Regulation, Neoplastic ; Humans ; Immunohistochemistry ; In Situ Hybridization, Fluorescence ; Male ; Middle Aged ; Neoplasm Staging ; p21-Activated Kinases ; genetics

OBJECTIVETo study the role of p21-activated kinase-4 (PAK4) in the occurrence, progression and metastasis of breast cancer.

METHODPAK4 expression was detected in 35 cases of normal breast, 22 breast cystic hyperplasia, 28 breast adenofibroma, 37 breast cancer (including 7 non-invasive cancer, 9 early invasive cancer and 21 invasive cancer) and 13 metastatic breast cancer tissues using immunohistochemistry for a comparison of PAK4 expression and distribution.

RESULTSPAK4 was expressed mainly in the cytoplasm of the cancer cells, occasionally in the cell nuclei, and virtually not expressed in the matrix surrounding the breast cells. PAK4 positivity rates increased in the order of normal breast tissues, benign changes (including breast cystic hyperplasea and breast adenoma), breast cancer and metastatic cancer tissues; in the cancer tissues, the positivity rates increased in the order of non-invasive breast tumor, early invasive tumor and invasive tumor tissues.

CONCLUSIONPAK4 is closely correlated to the progression and metastasis of breast cancer and may become a new diagnostic and therapeutic target of breast cancer.

Adult ; Aged ; Biomarkers, Tumor ; genetics ; metabolism ; Breast Neoplasms ; metabolism ; pathology ; Female ; Humans ; Middle Aged ; Neoplasm Invasiveness ; Neoplasm Metastasis ; Young Adult ; p21-Activated Kinases ; genetics ; metabolism

OBJECTIVETo investigate the effects of epigallocatechin-3-gallate (EGCG) on the proliferation of SW620 cells and the expression of PAK1 gene.

METHODSHuman colonic cancer cell line SW620 was treated with EGCG at 40, 60 and 80 micromol/L and cultured in RPMI 1640 medium for 0, 24, 48 and 72 h. The proliferation of SW620 cells was observed by MTT assay before and after EGCG treatment, and the expression of PAK1 protein was observed by Western blotting.

RESULTSSW620 cells treated with EGCG displayed a slowed growth in comparison with the control cells, and the growth rate decreased with the increase of EGCG concentration. PAK1 protein expression was lowered in SW620 cells after EGCG treatment for 48 h.

CONCLUSIONEGCG can inhibit the proliferation and partially reduce the expression of PAK1 protein in SW620 cells.

Blotting, Western ; Catechin ; analogs & derivatives ; pharmacology ; Cell Line, Tumor ; Cell Proliferation ; drug effects ; Colonic Neoplasms ; genetics ; pathology ; Gene Expression Regulation, Neoplastic ; drug effects ; Humans ; p21-Activated Kinases ; metabolism

BACKGROUNDPeg-Interferon-α treatment is expensive and associated with considerable adverse effects, selection of patients with the highest probability of response is essential for clinical practice. The objective of this study was to assess the relationship between the gene polymorphisms of interleukin-28 (IL-28), p21-activated protein kinase 4 (PAK4) and the response to interferon treatment in chronic hepatitis B patients.

METHODSTwo hundred and forty interferon-naive treatment HBeAg seropositive chronic hepatitis B patients were enrolled in the present prospective nested case-control study. Peripheral blood samples were collected, including 92 with favorable response and 148 without response to the interferon treatment. Rs8099917, rs12980602, and rs9676717 SNP was genotyped using matrix assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS).

RESULTSIL-28 genotype was not associated with response to interferon treatment (OR for GT/GG vs. TT, 0.881 (95%CI 0.388 - 2.002); P = 0.762; OR for CT/CC vs. TT, 0.902 (95%CI 0.458 - 1.778); P = 0.766). Rs9676717 in PAK4 genotype was independently associated with the response (OR for CT/CC vs. TT, 0.524 (95%CI 0.310 - 0.888); P = 0.016). When adjusting for age, gender, smoking, drinking, levels of hepatitis B virus DNA, and alanine aminotransferase (ALT), rs9676717 genotype TT appeared to be associated with a higher probability of response for interferon treatment (OR, 0.155 (95%CI 0.034 - 0.700); P = 0.015).

CONCLUSIONGenotype TT for rs9676717 in PAK4 gene and no drinking may be predictive of the interferon-a treatment success.

Adult ; Case-Control Studies ; Female ; Genotype ; Hepatitis B, Chronic ; drug therapy ; genetics ; Humans ; Interferon-alpha ; therapeutic use ; Interleukins ; genetics ; Male ; Middle Aged ; Polymorphism, Single Nucleotide ; Prospective Studies ; p21-Activated Kinases ; genetics

OBJECTIVETo clone PAK5-N terminal sequence for expression in E. coli to prepare its polyclonal antibody, and examine the role of PAK5 in dental germ cells.

METHODSBased on human PAK5 cDNA sequence, PCR primers were designed to amplify PAK5-N terminal sequence. The PCR product was cloned into the expression vector pGEX-4T-1 EcoRI/XhoI sites, and the recombinant plasmids were identified by agarose gel electrophoresis followed by DNA sequence analysis. The recombinant plasmids were transformed into E. coli BL21 and the expression of GST-fusion protein was induced by IPTG. Glutathione-Sepharose beads were used to purify GST-fusion PAK5-N-terminal fragment. Anti-PAK5 polyclonal antibody was obtained in immunizing rabbits with purified GST-PAK5 N-terminal fusion protein, and the antibodies were purified by protein A beads and used for detection of PAK5 expression in dental germ cells.

RESULTS AND CONCLUSIONSWe successfully cloned PAK5-N terminal gene fragment, and achieved protein expression, purification and production of PAK5-NT polyclonal antibody. The results of Western blotting indicated that PAK5 can be highly expressed in the dental germ cells, suggesting that PAK5 may play an important role in biological function of dental germ cells.

Animals ; Antibodies, Monoclonal ; biosynthesis ; genetics ; immunology ; Base Sequence ; Blotting, Western ; Cloning, Molecular ; Humans ; Molecular Sequence Data ; Rabbits ; Recombinant Fusion Proteins ; biosynthesis ; genetics ; immunology ; Sequence Analysis, DNA ; Tooth Germ ; cytology ; embryology ; enzymology ; p21-Activated Kinases ; biosynthesis ; genetics ; immunology