Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P01185 (vasopressin)
 23,126 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We investigated whether the motor protein cytoplasmic dynein and dynactin, a protein complex thought to link dynein with vesicles, are present in rat renal collecting ducts and associated with aquaporin-2 (AQP2)-bearing vesicles. Immunoblotting demonstrated cytoplasmic dynein heavy and intermediate chains in kidney, with relative expression levels of inner medulla > outer medulla > cortex. In addition to being present in cytoplasmic fractions, dynein was abundant in membrane fractions enriched for intracellular vesicles. Dynactin was also abundant in membrane fractions enriched for intracellular vesicles. Furthermore, both dynactin and dynein were present in vesicles specifically immunoisolated using anti-AQP2 antibodies. Immunocytochemistry revealed labeling for dynein in the collecting duct principal cells with a pattern consistent with labeling of intracellular vesicles. Moreover, quantitative double immunogold labeling confirmed colocalization of AQP2 and dynein in the same vesicles at the electron microscopic level. Thus the microtubule-associated motor protein dynein and the associated dynactin complex are present in rat renal collecting duct principal cells and are associated with intracellular vesicles, including those bearing AQP2, consistent with the view that dynein and dynactin are involved in vasopressin-regulated trafficking of AQP2-bearing vesicles.
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PMID:Dynein and dynactin colocalize with AQP2 water channels in intracellular vesicles from kidney collecting duct. 948 34

Arginine-vasopressin (AVP) regulates water reabsorption in renal collecting duct principal cells. Its binding to Gs-coupled vasopressin V2 receptors increases cyclic AMP (cAMP) and subsequently elicits the redistribution of the water channel aquaporin-2 (AQP2) from intracellular vesicles into the plasma membrane (AQP2 shuttle), thereby facilitating water reabsorption from primary urine. The AQP2 shuttle is a paradigm for cAMP-dependent exocytic processes. Using sections of rat kidney, the AQP2-expressing cell line CD8, and primary principal cells, we studied the role of the motor protein myosin Vb, its vesicular receptor Rab11, and the myosin Vb- and Rab11-binding protein Rab11-FIP2 in the AQP2 shuttle. Myosin Vb colocalized with AQP2 intracellularly in resting and at the plasma membrane in AVP-treated cells. Rab11 was found on AQP2-bearing vesicles. A dominant-negative myosin Vb tail construct and Rab11-FIP2 lacking the C2 domain (Rab11-FIP2-DeltaC2), which disrupt recycling, caused condensation of AQP2 in a Rab11-positive compartment and abolished the AQP2 shuttle. This effect was dependent on binding of myosin Vb tail and Rab11-FIP2-DeltaC2 to Rab11. In summary, we identified myosin Vb as a motor protein involved in AQP2 recycling and show that myosin Vb- and Rab11-FIP2-dependent recycling of AQP2 is an integral part of the AQP2 shuttle.
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PMID:A Role of myosin Vb and Rab11-FIP2 in the aquaporin-2 shuttle. 1715 9

Dehydration activates the vasopressinergic system of the hypothalamus. We analyzed the effects of dehydration induced by water deprivation for 3 days on the activities of ERK1/2 and transcription factors, Elk1 and cAMP response element-binding protein (CREB) in vasopressinergic neurons, as well as the distribution and level of the motor protein, kinesin, in the hypothalamo-neurohypophyseal system. We showed that dehydration resulted in enhanced vasopressin (VP) expression and activation of CREB, and increased the activity of the MEK/ERK/Elk1 pathway in magnocellular neurons of the supraoptic nucleus. The activation of VP secretion was associated also with accumulation of phospho-ERK1/2 in the VP-ergic terminals of the posterior lobe of the pituitary. Analysis of the amount and distribution of kinesin and SNAP25, the proteins associated with transport and secretion, demonstrated that dehydration enhanced kinesin content in the perikarya of magnocellular neurons in the supraoptic nucleus and decreased kinesin and SNAP25 levels in the posterior pituitary. ERK1/2 and ERK1/2-dependent transcription factors, Elk1 and CREB, participate in the regulation of dehydration-evoked VP expression. We propose that ERK1/2 and kinesin participate in regulation of anterograde transport of VP dense core vesicles.
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PMID:Role of the ERK signaling pathway in regulating vasopressin secretion in dehydrated rats. 2405 64

Mammalian class IX myosin Myo9a is a single-headed, actin-dependent motor protein with Rho GTPase-activating protein activity that negatively regulates Rho GTPase signaling. Myo9a is abundantly expressed in ciliated epithelial cells of several organs. In mice, genetic deletion of Myo9a leads to the formation of hydrocephalus. Whether Myo9a also has essential functions in the epithelia of other organs of the body has not been explored. In the present study, we report that Myo9a-deficient mice develop bilateral renal disease, characterized by dilation of proximal tubules, calyceal dilation, and thinning of the parenchyma and fibrosis. These structural changes are accompanied by polyuria (with normal vasopressin levels) and low-molecular-weight proteinuria. Immunohistochemistry revealed that Myo9a is localized to the circumferential F-actin belt of proximal tubule cells. In kidneys lacking Myo9a, the multiligand binding receptor megalin and its ligand albumin accumulated at the luminal surface of Myo9a-deficient proximal tubular cells, suggesting that endocytosis is dysregulated. In addition, we found, surprisingly, that levels of murine diaphanous-related formin-1, a Rho effector, were decreased in Myo9a-deficient kidneys as well as in Myo9a knockdown LLC-PK1 cells. In summary, deletion of the Rho GTPase-activating protein Myo9a in mice causes proximal tubular dilation and fibrosis, and we speculate that downregulation of murine diaphanous-related formin-1 and impaired protein reabsorption contribute to the pathophysiology.
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PMID:Rho GAP myosin IXa is a regulator of kidney tubule function. 2613 56