β subunit affects Na and K affinities of Na/K-ATPase: Na and K affinities of a hybrid Na/K-ATPase composed of insect α and mammalian β subunits.

The affinity for K of silkworm Na/K-ATPase, which is composed of α and β subunits, is remarkably lower than that of mammalian Na/K-ATPase, with a slightly higher affinity for Na. Because the α subunit had more than 70% identity to the mammalian α subunit in the amino acid sequence, whereas the β subunit, a glycosylated protein, had less than 30% identity to the mammalian β subunit, it was suggested that the β subunit was involved in the affinities for Na and K of Na/K-ATPase. To confirm this hypothesis, we examined whether replacing the silkworm β subunit with the mammalian β subunit affected the affinities for Na and K of Na/K-ATPase.

Golgi stress induces upregulation of the ER-Golgi SNARE Syntaxin-5, altered βAPP processing, and Caspase-3-dependent apoptosis in NG108-15 cells.

The involvement of secretory pathways and Golgi dysfunction in neuronal cells during Alzheimer's disease progression is poorly understood. Our previous overexpression and knockdown studies revealed that the intracellular protein level of Syntaxin-5, an endoplasmic reticulum-Golgi soluble N-ethylmaleimide-sensitive factor-attachment protein receptor (SNARE), modulates beta-amyloid precursor protein processing in neuronal cells. We recently showed that changes in endogenous Syntaxin-5 protein expression occur under stress induction.

Inhibition of the human secretory pathway Ca, Mn-ATPase1a by 1,3-thiazole derivatives.

The human Golgi/secretory pathway Ca,Mn-ATPase 1 (hSPCA1) transports Ca and Mn into the Golgi lumen. Studies of the biological functions of hSPCA1 are limited by a lack of selective pharmacological tools for SPCA1 inhibition. The aim of this study was therefore to identify compounds that specifically inhibit hSPCA1 activity.