The Tpr1 protein of Schizosaccharomyces pombe, when overproduced in S. cerevisiae exhibiting a Δtrk1,2 K+ uptake deficient phenotype, restored growth and inward K+ currents and currents of other alkali metal ions. The protein is 1039aas long and exhibits several 34aa TRP degenerate repeats that probably mediate protein-protein interactions. Many other proteins in eukaryotes, bacteria and arachaea are homologous. These homologues include a mouse phosphoprotein, a developmental protein in Dictyostelium, a cell division control protein of Borrelia burgdorferi, a gibberellin action negative regulator in Hordeum vulgare, and an Ο-linked N-acetyl glucosamine transferase of Methanobacterium thermoautotrophicum. These proteins are of widely varying sizes. The Tpr1 protein has been proposed to function as an auxillary protein, interacting with and activating K+ carriers.