Structural relationships between the NADH dehydrogenases of Paracoccus denitrificans and bovine heart mitochondria as revealed by immunological cross-reactivities

AbstractAn antibody raised against two subunits (Mr, 48000 and 25000) of NADH dehydrogenase from Paracoccusdenitrificans cross-reacts with one of more than 20 polypeptides that form the bovine heart mitochondrial NADH dehydrogenase. The cross-reacting subunit has Mr, 51000 and is believed to be the NADH-binding subunit of the enzyme. Antibodies raised against certain subunits of the bovine heart NADH dehydrogenase were tested for cross-reactivity withP. denitrificans cytoplasmic membranes. Of those tested, only one, an antibody specific for the 49 kDa subunit of mitochondrial NADH dehydrogenase, cross-reacted with the bacterial membranes. It recognised a polypeptide of approximate Mr, 46000. This is an indication for a previously undetected third subunit of NADH dehydrogenase from P. denitrificans. The immunological crossreactions indicate that the NADH dehydrogenases from P. denitrificans and bovine heart mitochondria are related structurally

Endoplasmic reticulum and lysosomal Ca2+ stores are remodelled in GBA1-linked Parkinson disease patient fibroblasts.

Mutations in β-glucocerebrosidase (encoded by GBA1) cause Gaucher disease (GD), a lysosomal storage disorder, and increase the risk of developing Parkinson disease (PD). The pathogenetic relationship between the two disorders is unclear. Here, we characterised Ca2+ release in fibroblasts from type I GD and PD patients together with age-matched, asymptomatic carriers, all with the common N370S mutation in β-glucocerebrosidase. We show that endoplasmic reticulum (ER) Ca2+ release was potentiated in GD and PD patient fibroblasts but not in cells from asymptomatic carriers. ER Ca2+ signalling was also potentiated in fibroblasts from aged healthy subjects relative to younger individuals but not further increased in aged PD patient cells. Chemical or molecular inhibition of β-glucocerebrosidase in fibroblasts and a neuronal cell line did not affect ER Ca2+ signalling suggesting defects are independent of enzymatic activity loss. Conversely, lysosomal Ca2+ store content was reduced in PD fibroblasts and associated with age-dependent alterations in lysosomal morphology. Accelerated remodelling of Ca2+ stores by pathogenic GBA1 mutations may therefore feature in PD