Pancreatic beta-cells express hepcidin, an iron-uptake regulatory peptide.

Body iron is involved in various vital functions. Its uptake in the intestine is regulated by hepcidin, a bioactive peptide originally identified in plasma and urine and subsequently in the liver. In the present study, we provide evidence at the transcriptional and translational levels that hepcidin is also expressed in the pancreas of rat and man.

Secretory granules of hypophyseal and pancreatic endocrine cells contain proteins of the neuronal postsynaptic density.

The PDZ domain-containing protein Shank is a master scaffolding protein of the neuronal postsynaptic density and directly or indirectly links neurotransmitter receptors and cell adhesion molecules to the actin-based cytoskeleton. ProSAP/Shank proteins have recently also been detected in several non-neuronal cells in which they are mostly concentrated in the apical subplasmalemmal cytoplasm. In contrast, we have previously reported a more widespread cytoplasmic immunostaining pattern for the ProSAP1/Shank2 protein in endocrine cells at the light-microscopic level.

Expression of postsynaptic density proteins of the ProSAP/Shank family in the thymus.

PSD95-DLG-ZO1 domain-containing proteins of the ProSAP/Shank family are major scaffolding proteins of the neuronal postsynaptic density which play a pivotal role in the linkage of membrane receptors to downstream signal effectors and the actin-based cytoskeleton. Recently, ProSAP1/Shank2 has also been localized in various non-neuronal cells where it may fulfill similar functions as in neurons. We now complement these data by the study of ProSAP/Shank expression at the mRNA and protein level in a primary lymphoid organ, i.

The clathrin interacting protein Clint/epsinR in rat testicular germ cells.

The plasma membrane and the trans-Golgi network (TGN) are major intracellular sites for clathrin-mediated membrane budding. Only recently has the clathrin interacting protein Clint/epsinR/enthoprotin been identified, which is thought to be involved in clathrin-dependent membrane budding from the TGN. Using immunocytochemistry, we now report the presence of Clint in the Golgi region of spermatocytes and spermatids of the rat testis.

Association of Caldendrin splice isoforms with secretory vesicles in neurohypophyseal axons and the pituitary.

Caldendrin is a neuronal calcium-binding protein, which is highly enriched in the postsynaptic density fraction and exhibits a prominent somato-dendritic distribution in brain. Two additional splice variants derive from the caldendrin gene, which have unrelated N-termini and were previously only detected in the retina. We now show that these isoforms are present in neurohypophyseal axons and on secretory granules of endocrine cells.

Brain synaptic junctional proteins at the acrosome of rat testicular germ cells.

Proteins of the presynaptic exocytic machinery have been found associated with the acrosome of male germ cells, suggesting that the sperm acrosome reaction and neurotransmission at chemical synapses may share some common mechanisms. To substantiate this hypothesis, we studied the expression and ultrastructural localization of prominent pre- and postsynaptic protein components in rat testis. The presynaptic membrane trafficking proteins SV2 and complexin, the vesicular amino acid transporters VGLUT and VIAAT, the postsynaptic scaffolding protein ProSAP/Shank, and the postsynaptic calcium-sensor protein caldendrin, could be identified in germ line cells.