Guamanian amyotrophic lateral sclerosis (ALS-G) and parkinsonism dementia (PD-G) have been epidemiologically linked to an environment severely deficient in calcium (Ca 2؉ ) and magnesium (Mg 2؉ ). Transient receptor potential melastatin 7 (TRPM7) is a bifunctional protein containing both channel and kinase domains that has been proposed to be involved in the homeostatic regulation of intracellular Ca 2؉ , Mg 2؉ , and trace metal ion concentration. There is evidence that TRPM7 is constitutively active and that the number of available channels is dependent on intracellular free Mg 2؉ levels. We found a TRPM7 variant in a subset of ALS-G and PD-G patients that produces a protein with a missense mutation, T1482I. Recombinant T1482I TRPM7 exhibits the same kinase catalytic activity as WT TRPM7. However, heterologously expressed T1482I TRPM7 produces functional channels that show an increased sensitivity to inhibition by intracellular Mg 2؉ . Because the incidence of ALS-G and PD-G has been associated with prolonged exposure to an environment severely deficient in Ca 2؉ and Mg 2؉ , we propose that this variant TRPM7 allele confers a susceptibility genotype in such an environment. This study represents an initial attempt to address the important issue of gene-environment interactions in the etiology of these diseases.amyotrophic lateral sclerosis ͉ calcium ͉ gene-environment interactions ͉ phosphorylation ͉ parkinsonism dementia

Streptococcus pneumoniae open reading frame SP0082 encodes a surface protein that contains four copies of a novel conserved repeat domain that bears no significant sequence similarity to proteins of known function. Homologous sequences from other streptococci contain two to six of these repeats, designated the SSURE (streptococcal surface repeat) domain. To investigate the functional role(s) of this domain, the third SSURE repeat of SP0082 sequence has been expressed in Escherichia coli, purified to homogeneity and characterized by biochemical and immunological methods. The expressed protein fragment was found to bind to fibronectin, but not to collagen or submaxillary mucin. Anti-SSURE antibodies recognized the corresponding protein on the surface of pneumococcal cells. These data identify S. pneumoniae SP0082 protein and its homologs in other streptococci as fibronectin-binding surface adhesins. The SSURE domain is likely to contain a novel protein fold, which was tentatively modeled using ab initio modeling methods.