Publications by authors named "Sarah Ribeiro-Milograna"

Breast cancer affects 1 in 8 women globally, and is the leading cause of cancer-related deaths in female patients. The majority of breast cancer cases are of unknown cause; few are linked to genetic predisposition, and some arise sporadically. Finding the cause of these sporadic cases is an important area in cancer research.

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Pigment aggregation in shrimp chromatophores is triggered by red pigment concentrating hormone (RPCH), a neurosecretory peptide whose plasma membrane receptor may be a G-protein coupled receptor (GPCR). While RPCH binding activates the Ca /cGMP signaling cascades, a role for cyclic AMP (cAMP) in pigment aggregation is obscure, as are the steps governing Ca release from the smooth endoplasmic reticulum (SER). A role for the antagonistic neuropeptide, pigment dispersing homone (α-PDH) is also unclear.

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The binding of red pigment concentrating hormone (RPCH) to membrane receptors in crustacean chromatophores triggers Ca²⁺/cGMP signaling cascades that activate cytoskeletal motors, driving pigment granule translocation. We investigate the distributions of microfilaments and microtubules and their associated molecular motors, myosin and dynein, by confocal and transmission electron microscopy, evaluating a functional role for the cytoskeleton in pigment translocation using inhibitors of polymer turnover and motor activity in vitro. Microtubules occupy the chromatophore cell extensions whether the pigment granules are aggregated or dispersed.

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Crustacean color change results partly from granule aggregation induced by red pigment concentrating hormone (RPCH). In shrimp chromatophores, both the cyclic GMP (3', 5'-guanosine monophosphate) and Ca(2+) cascades mediate pigment aggregation. However, the signaling elements upstream and downstream from cGMP synthesis by GC-S (cytosolic guanylyl cyclase) remain obscure.

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Crustacean color change results from the differential translocation of chromatophore pigments, regulated by neurosecretory peptides like red pigment concentrating hormone (RPCH) that, in the red ovarian chromatophores of the freshwater shrimp Macrobrachium olfersi, triggers pigment aggregation via increased cytosolic cGMP and Ca(2+) of both smooth endoplasmatic reticulum (SER) and extracellular origin. However, Ca(2+) movements during RPCH signaling and the mechanisms that regulate intracellular [Ca(2+)] are enigmatic. We investigate Ca(2+) transporters in the chromatophore plasma membrane and Ca(2+) movements that occur during RPCH signal transduction.

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