Protein disulfide isomerase (PDI), secreted from platelets and endothelial cells after injury, is required for thrombus formation. The effect of platelet and endothelial cell granule contents on PDI-mediated thrombus formation was studied by intravital microscopy using a mouse model of Hermansky-Pudlak syndrome in which platelet dense granules are absent. Platelet deposition and fibrin generati...

Albinism is an inherited abnormality of melanin synthesis with incidence of one per 20,000 births. Its clinical manifestations are related to the reduction or absence of pigmentation in the visual system and/or the skin and teguments. The clinical spectrum of Oculocutaneous Albinism (OCA) has four types ranging from OCA 1 - 4, of which OCA 1, A-1 is the most severe form. Partial cutaneous albin...

A 55-year-old man had oculocutaneous albinism and a history of frequent bruising following minimal trauma. The simultaneous occurrence of these features was first described by Hermansky and Pudlak in 1959. The Hermansky-Pudlak syndrome follows an autosomal recessive trait and is most frequently found in Puerto Rico and in the Swiss alps. It consists of the triad phenotype of hypopigmentation, p...

Hermansky-Pudlak Syndrome is a rare form of albinism, affecting approximately one in 500,000 to one in 1,000,000 non-Hispanic individuals. The syndrome is more commonly found in Hispanics, where one in 18,00 individuals in Northwestern Puerto Rico are impacted. Because of the rarity of this chronic condition, patients often face challenges in their ability to cope with the diagnosis. A phenomen...

Inherited platelet function disorders (IPFDs) encompass a heterogeneous group of haemorrhagic diseases caused by congenital defects of platelets function affecting various elements of the platelet physiology (membrane receptors, intraplatelet signalling proteins, granules), and leading to different clinical manifestations (1–3). Platelets have three types of secretory granules that differ in th...

The Hermansky-Pudlak syndrome defines a group of genetic disorders characterized by defective lysosome-related organelles such as melanosomes and platelet dense bodies. Hermansky-Pudlak syndrome can be caused by mutations of at least four genes in humans and 15 genes in mice. One of these genes is mutated in the pallid mouse strain and encodes a novel protein named pallidin (L. Huang, Y. M. Kuo...

Vesicle biogenesis machinery components such as coat proteins can interact with the actin cytoskeleton for cargo sorting into multiple pathways. It is unknown, however, whether these interactions are a general requirement for the diverse endosome traffic routes. In this study, we identify actin cytoskeleton regulators as previously unrecognized interactors of complexes associated with the Herma...