Tissue distribution and subcellular localization of the family of Kidney Ankyrin Repeat Domain (KANK) proteins

Kidney Ankyrin Repeat-containing Proteins (KANKs) comprise a family of four evolutionary conserved proteins (KANK1 to 4) that localize to the belt of mature focal adhesions (FAs) where they regulate integrin-mediated adhesion, actomyosin contractility, and link FAs to the cortical microtubule stabilization complex (CMSC). The human KANK proteins were first identified in kidney and have been associated with kidney cancer and nephrotic syndrome. Here, we report the distributions and subcellular localizations of the four Kank mRNAs and proteins in mouse tissues. We found that the KANK family members display distinct and rarely overlapping expression patterns. Whereas KANK1 is expressed at the basal side of epithelial cells of all tissues tested, KANK2 expression is mainly observed at the plasma membrane and/or cytoplasm of mesenchymal cells and KANK3 exclusively in vascular and lymphatic endothelial cells. KANK4 shows the least widespread expression pattern and when present, overlaps with KANK2 in contractile cells, such as smooth muscle cells and pericytes. Our findings show that KANKs are widely expressed in a cell type-specific manner, which suggests that they have cell- and tissue-specific functions.     

Complex rearrangement involving 9p deletion and duplication in a syndromic patient: genotype/phenotype correlation and review of the literature

We describe a 7-year-old boy with a complex rearrangement involving the whole short arm of chromosome 9 defined by means of molecular cytogenetic techniques. The rearrangement is characterized by a 18.3 Mb terminal deletion associated with the inverted duplication of the adjacent 21,5 Mb region. The patient shows developmental delay, psychomotor retardation, hypotonia. Other typical features of 9p deletion (genital disorders, midface hypoplasia, long philtrum) and of the 9p duplication (brachycephaly, down slanting palpebral fissures and bulbous nasal tip) are present. Interestingly, he does not show trigonocephaly that is the most prominent dysmorphism associated with the deletion of the short arm of chromosome 9. Patient's phenotype and the underlying flanking opposite 9p imbalances are compared with that of reported patients and the proposed critical regions for 9p deletion and 9p duplication syndromes.     

KANK1对子宫内膜癌细胞增殖及迁移的影响

摘要 目的：研究KANK1在子宫内膜癌中的表达以及对子宫内膜癌细胞增殖及迁移的影响。方法：（1）TCGA数据库分析KANK1在子宫内膜癌中的表达和生存期分析。（2）采用实时荧光定量聚合酶链反应验证转染KANK1质粒的效果。采用Ishikawa和ECC1这两种子宫内膜癌细胞来探讨KANK1对子宫内膜癌的细胞周期和凋亡的影响。通过Western blot检测细胞周期相关蛋白的表达,以及流式细胞术检测细胞周期和凋亡水平。（3）通过Transwell小室实验和划痕实验检测细胞的侵袭和转移能力。结果：TCGA数据库分析发现KANK1在子宫内膜癌中低表达且与患者预后良好相关。过表达KANK1下调了Cyclin D1和Cyclin D2的蛋白水平,并将细胞周期阻滞在G1期。流式细胞术检测发现过表达KANK1组的细胞凋亡水平（Ishikawa：22.7%;ECC1：19.0%）比对照组（Ishikawa：18.1%;ECC1：15.3%）高,差异具有统计学意义。Transwell迁移和侵袭实验结果表明过表达KANK1组的子宫内膜癌细胞侵袭和转移能力减弱。结论：本研究证明了KANK1在子宫内膜癌中发挥抑癌作用。KANK1高表达与子宫内膜癌的预后良好成正相关。KANK1通过抑制癌细胞周期和促进肿瘤细胞凋亡发挥抑制子宫内膜癌增殖的作用。此外,KANK1抑制了子宫内膜癌的侵袭和转移。     

Population-scale analysis of human microsatellites reveals novel sources of exonic variation

Using our microsatellite specific genotyping method, we analyzed tandem repeats, which are known to be highly variable with some recognized as biomarkers causative of disease, in over 500 individuals who were exon sequenced in a 1000 Genomes Project pilot study. We were able to genotype over 97% of the microsatellite loci in the targeted regions. A total of 25,115 variations were observed, including repeat length and single nucleotide polymorphisms, corresponding to an average of 45.6 variations per individual and a density of 1.1 variations per kilobase. Standard variant detection did not report 94.2% of the exonic repeat length variations in part because the alignment techniques are not ideal for repetitive regions. Additionally some standard variation detection tools rely on a database of known variations, making them less likely to call repeat length variations as only a small percent of these loci (~ 6000) have been accurately characterized. A subset of the hundreds of non-synonymous variations we identified was experimentally validated, indicating an accuracy of 96.5% for our microsatellite-based genotyping method, with some novel variants identified in genes associated with cancer. We propose that microsatellite-based genotyping be used as a part of large scale sequencing studies to identify novel variants.     

Novel chromosomal translocation t(11;9)(p15;p23) involving deletion and duplication of 9p in a girl associated with autism and mental retardation

We describe a 5-year-old girl presented with autism and mental retardation features. Conventional karyotyping revealed a novel unidirectional translocation t(11;9)(p15;p23). HumanCytoSNP-12 Chip analysis identified a 13 Mb deletion from 9p24.3 to 9p23 and a 12.5Mb duplication from 9p23 to 9p21.2. The karyotype was described as 45,XX,psu dic(11; 9)(p15;p23), which was reported for the first time here. The deleted region, extending from 9p24.3 to 9p23, overlaps with the candidate region for monosomy 9p syndrome and contains a potential autism spectrum disorders (ASD) locus. The duplication region extending from 9p23 to 9p21.2 was previously identified as a critical region for the 9p duplication syndrome. These results suggested that the apparently balanced de novo translocations could produce cryptic deletions or duplications, and the precise mapping of the abnormal area may improve clinical management.     

Nephrotic-syndrome-associated mutation of KANK2 induces pathologic binding competition with physiological interactor KIF21A

Nephrotic syndrome (NS) is a common kidney disorder caused by dysfunction of the glomerular filtration barrier. Some genetic mutations identified in NS patients cause amino acid substitutions of kidney ankyrin repeat-containing (KANK) proteins, which are scaffold proteins that regulate actin polymerization, microtubule targeting, and cell adhesion via binding to various molecules, including the kinesin motor protein KIF21A. However, the mechanisms by which these mutations lead to NS are unclear. Here, we unexpectedly found that the eukaryotic translation initiation factor 4A1 (eIF4A1) interacts with an NS-associated KANK2 mutant (S684F) but not the wild-type protein. Biochemical and structural analyses revealed that the pathological mutation induces abnormal binding of eIF4A1 to KANK2 at the physiological KIF21A-binding site. Competitive binding assays further indicated that eIF4A1 can compete with KIF21A to interact with the S684F mutant of KANK2. In cultured mouse podocytes, this S684F mutant interfered with the KANK2/KIF21A interaction by binding to eIF4A1, and failed to rescue the focal adhesion or cell adhesion that had been reduced or morphologically changed by KANK2 knockout. These structural, biochemical, and cellular results not only provide mechanistic explanations for the podocyte defects caused by the S684F mutation, but also show how a gain-of-binding mutation can lead to a loss-of-function effect.