MINPP1 antibody

Background of MINPP1 antibody

Multiple inositol polyphosphatase is only enzyme known to hydrolyze the abundant metabolites of phosphorylated inositol signaling molecule inositol penta- and hexa-phosphates. Sequence analysis of plant and fruit fly MINPP homolog¡¦s supports the hypothesis that the MINPP enzymes constitute a distinct evolutionary group within the histidine phosphatase family. Minpp chicken homolog is a histdine phosphatase HiPER1 that has a role on growth plate chondrocyte differentiation. The human and murine homolog of Minpp1 mRNA expression was found in variety of tissues compared to much restricted expression of chick homolog HiPER1. The murine and human Minpp is 80% homologous to rat protein and 56% to HiPER (1). During osteogenesis in growth plate chondrocytes the levels of Minpp initially increase 2-3fold and then reduced to the basal levels with a concomitant decrease in Ins5 but no change in Ins6 levels in ATDC5 cells (2). The Minpp1 is largely a endoplasmic reticulum associated protein, however, a truncated for Minpp1 has been shown in the cytoplasm of cells that might be involved in conversion of Ins5 and Ins6 in to a Ca second messenger 1, 4, 5 inositol triphosphatse in independent inositol lipid breakdown. Minpp1 is compartmentalized in the endoplasmic reticulum (ER) lumen. The Minpp-deficient mice are viable, fertile and without obvious defect but have 30-40% higher Ins5 and Ins6 levels that are reduced to normal by reintroducing Minpp. Reintroduction of Minpp led to generation of a truncated Minpp-cytosolic form, lacking its Er targeting N-terminus that dephosphorylates the polyinositol phosphtates (3).
The human Minpp1 is localized on human chromosome10q23, the assignment of Minpp1 on chromosome 10 paces it proximal to tumor suppressor protein Pten on chromosome 10 that is most frequently mutated in cancer (4). The comparison of human Minpp1 and chick HiPER1 revealed significant homology in the core protein but the ER targeting domain was divergent. The catalytic domain has a Histidine, replacing with Alanine led to complete loss of activity (5). Minpp1 is a 487amino acid protein, approximately 58kDa, is expressed in multiple splice variant forms.