P rotein phosphorylation at tyrosine is a key regulatory event that modulates intracellular signaling pathways involved in signal transduction. Protein tyrosine phosphatase (PTP)-1B is a ubiquitously expressed protein (1) that catalyzes the dephosphorylation of proteins at tyrosyl residues. PTP-1B has been implicated (2-4) in negatively regulating insulin signaling by dephosphorylating the phosphotyrosine residues of the insulin receptor kinase activation segment of the insulin receptor. In mouse models, disruption of the PTPN1 gene resulted in increased insulin sensitivity and resistance to diet-induced obesity (5,6). Further evidence for the role of PTP-1B in insulin sensitivity is seen in knockout mice, in which there was increased phosphorylation of the insulin receptor in liver and muscle tissue (5,6). These observations suggest that PTP-1B plays a role in modulating signal transduction, and defects in PTP-1B expression could lead to insulin resistance.The 10 exons of PTPN1 span Ͼ74 kb of chromosome 20q13.13, with the first intron containing Ͼ50 kb of the sequence. Several investigators (7-9) have searched PTPN1 for DNA sequence variants, e.g., single nucleotide polymorphisms (SNPs). Variation within the coding region of PTPN1 is relatively uncommon. Echwald et al. (7) identified a P387L variant that was found in 2.6% of type 2 diabetic individuals and 1% of healthy control subjects, which showed evidence of impaired in vitro serine phosphorylation of the PTP-1B peptide. Mok et al. (8) identified a 981C3 T polymorphism (5% minor allele frequency) that corresponded to a silent mutation in the PTP-1B protein

Genome-wide analysis of a large set of prostate cancer families indicates new areas of the genome that may harbor prostate cancer susceptibility genes. Specifically, our linkage results suggest that there is a prostate cancer susceptibility gene on chromosome 17 that is independent of ELAC2. Further research including combined analyses of independent genome-wide scan data may clarify the most important regions for future investigation.

Adiponectin, coded for by the APM1 gene, is a novel adipocyte-derived hormone implicated in energy homeostasis and obesity. Several genetic studies have observed evidence of association between APM1 gene polymorphisms and features of the metabolic syndrome, such as insulin resistance and obesity. As part of a comprehensive genetic analysis of the APM1 gene, we have screened 96 unrelated individuals for polymorphisms in the promoter, coding regions, and 3'untranslated region (UTR). Three promoter single-nucleotide polymorphisms (SNPs), two rare coding SNPs (G113A and T1233C), and 13 SNPs in the 3'UTR were identified. Eighteen SNPs were genotyped in 811 Hispanic individuals from 45 families in the IRAS Family Study (IRASFS). SNPs were tested for association with six obesity quantitative traits (body mass index, waist, waist:hip ratio, subcutaneous adipose tissue, visceral adipose tissue, and visceral:subcutaneous ratio). Significant evidence of association to at least one of the obesity traits was identified in seven of the 18 SNPs (<0.001-0.05). The promoter SNP INS CA-11156 was the most consistently associated SNP and was associated significantly with all measures of obesity, except the visceral:subcutaneous ratio (P-values 0.009-0.03). Haplotype analysis supported this evidence of association, with haplotypes containing an insertion of one CA repeat at position -11156 consistently being associated with lower obesity values (P-value <0.001-0.05). The adiponectin polymorphisms, in particular those in the promoter region, thus show significant association with obesity measures in the Hispanic population. Additional studies are needed to confirm our findings and determine which polymorphism causes the functional effect.

OBJECTIVE-We previously detected an association between a region of the estrogen receptor-␣ (ESR1) gene and type 2 diabetes in an African-American case-control study; thus, we investigated this region for associations with the metabolic syndrome and its component traits in African-American families from the Insulin Resistance Atherosclerosis Family Study. RESEARCH DESIGN AND METHODS-A total of 17 single nucleotide polymorphisms (SNPs) from a contiguous 41-kb intron 1-intron 2 region of the ESR1 gene were genotyped in 548 individuals from 42 African-American pedigrees. Generalized estimating equations were computed using a sandwich estimator of the variance and exchangeable correlation to account for familial correlation.RESULTS-Significant associations were detected between ESR1 SNPs and the metabolic syndrome (P ϭ 0.005 to P ϭ 0.029), type 2 diabetes (P ϭ 0.001), insulin sensitivity (P ϭ 0.0005 to P ϭ 0.023), fasting insulin (P ϭ 0.022 to P ϭ 0.033), triglycerides (P ϭ 0.021), LDL (P ϭ 0.016 to P ϭ 0.034), cholesterol (P ϭ 0.046), BMI (P ϭ 0.016 to P ϭ 0.035), waist circumference (P ϭ 0.012 to P ϭ 0.023), and subcutaneous adipose tissue area (P ϭ 0.016).CONCLUSIONS-It appears likely that ESR1 contributes to type 2 diabetes and CVD risk via pleiotropic effects, leading to insulin resistance, a poor lipid profile, and obesity. Diabetes 56: 2135-2141, 2007

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