Two aquaporins, multiple ways of assembly

Jozefkowicz, Cintia; Scochera, Florencia; Alleva, Karina

doi:10.1080/19336950.2016.1206371

Cited by 6 publications

(7 citation statements)

References 8 publications

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“…As one of the gene families that have been receiving an increased amount of attention from researchers in recent years, AQPs constitute an important route of water transportation that is separate from simple diffusion (18). Previous studies have indicated that AQPs have a regulatory role in functions associated with the mammalian reproductive system and affect the formation of the embryo sac; they may cause changes in the uterine cavity �uid at the implantation stage and the formation of the oviduct (19).…”

Section: Discussionmentioning

confidence: 99%

AQP8 and AQP9 expression in patients with polycystic ovary syndrome and its association with in vitro fertilization‑embryo transfer outcomes

Xiong

Wang

et al. 2019

Exp Ther Med

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The aim of the present study was to investigate aquaporin (AQP)8 and AQP9 expression in patients with polycystic ovary syndrome (PCOS) and its association with in vitro fertilization-embryo transfer (IVF-ET) outcomes. A total of 45 patients with PCOS undergoing IVF-ET (test group) and 50 patients with oviduct obstruction or ovarian cyst (control group) were assessed for the mRNA expression of AQP8 and AQP9 in ovarian tissues by reverse transcription-quantitative (RT-q)PCR. The levels of luteinizing hormone, anti-mullerian hormone and testosterone were determined, which were revealed to be significantly different between the two groups (P<0.05). The RT-qPCR results indicated that AQP8 expression in the control group was lower than that in the test group (t=37.75, P<0.01), whereas AQP9 expression in the control group was higher than that in the test group (t=19.59, P<0.01). The number of eggs obtained in the group with high AQP8 expression was significantly lower than that in the group with low AQP8 expression (t=2.64, P<0.01). The number of high-quality embryos in the high AQP8 expression group was not significantly different from that in the low AQP8 expression group (t=1.02, P>0.05). The pregnancy rate in patients with high AQP9 expression was higher than that in the low AQP9 expression group (P<0.05) and the abortion rate in the former was lower than that in the latter (P<0.05). In conclusion, AQP8 and AQP9 are differentially expressed in ovarian tissues of patients with PCOS vs. normal control subjects. The expression of AQP8 is closely associated with the occurrence and development of oocytes, whereas the expression of AQP9 is associated with the success rate of pregnancy in patients with PCOS.

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Section: Discussionmentioning

confidence: 99%

AQP8 and AQP9 expression in patients with polycystic ovary syndrome and its association with in vitro fertilization‑embryo transfer outcomes

Xiong

Wang

et al. 2019

Exp Ther Med

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“…To study cooperativity in PIP AQPs it must be considered that these channels can hetero‐oligomerize, which means that several assemblies with different stoichiometries are possible within a single cell expressing a minimum of two paralogues . So, to investigate the cooperative response of PIP species in the heterologous expression system of Xenopus oocytes, we injected cRNA coding for PIP2 monomers, or for PIP2‐PIP1 dimers, and performed water transport experiments.…”

Section: Two‐stage Models For Pip Cooperativitymentioning

confidence: 99%

Cooperativity in proton sensing by PIP aquaporins

et al. 2018

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One of the most intriguing properties of plasma membrane intrinsic protein (PIP) aquaporins (AQPs) is their ability to modulate water transport by sensing different levels of intracellular pH through the assembly of homo‐ and heterotetrameric molecular species in the plasma membrane. In this work, using a phenomenological modeling approach, we demonstrate that cooperativity in PIP biological response cannot be directly attributed to a cooperative proton binding, as it is usually considered, since it could also be the consequence of a cooperative conformation transition between open and closed states of the channel. Moreover, our results show that, when mixed populations of homo‐ and heterotetrameric PIP channels are coexpressed in the plasma membrane of the same cell, the observed decrease in the degree of positive cooperativity would result from the simultaneous presence of molecular species with different levels of proton sensing. Indeed, the random mixing between different PIP paralogues as subunits in a single tetramer, plus the possibility of mixed populations of homo‐ and heterotetrameric PIP channels widen the spectrum of cooperative responses of a cell membrane. Our approach offers a deep understanding of cooperative transport of AQP channels, as members of a multiprotein family where the relevant proton binding sites of each member have not been clearly elucidated yet.

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“…Interestingly, in Bv PIP2;2CT1;1‐ Bv PIP1;1 co‐expression, where all CT are short, pH 0,5 is ~ 6.8, but in Bv PIP2;2CT1;1‐ Bv PIP2;2 co‐expression, with a mixed population of long and short CT, pH 0,5 is ~6.6. This last result contrasts with the higher pH 0.5 value found for Bv PIP2;2‐ Bv PIP1;1 heterotetramers (~ 6.8) [11,30]. We suspect that, in heterotetramers, PIP1 NT plays a role on PIP2 long CT detaching from a neighboring loopD, a function that PIP2 NT cannot accomplish.…”

Section: Discussionmentioning

confidence: 66%

PIP aquaporin pH‐sensing is regulated by the length and charge of the C‐terminal region

et al. 2021

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Plant PIP aquaporins play a central role in controlling plant water status. The current structural model for PIP pH‐gating states that the main pH sensor is located in loopD and that all the mobile cytosolic elements participate in a complex interaction network that ensures the closed structure. However, the precise participation of the last part of the C‐terminal domain (CT) in PIP pH gating remains unknown. This last part has not been resolved in PIP crystal structures and is a key difference between PIP1 and PIP2 paralogues. Here, by a combined experimental and computational approach, we provide data about the role of CT in pH gating of Beta vulgaris PIP. We demonstrate that the length of CT and the positive charge located among its last residues modulate the pH at which the open/closed transition occurs. We also postulate a molecular‐based mechanism for the differential pH sensing in PIP homo‐ or heterotetramers by performing atomistic molecular dynamics simulations (MDS) on complete models of PIP tetramers. Our findings show that the last part of CT can affect the environment of loopD pH sensors in the closed state. Results presented herein contribute to the understanding of how the characteristics of CT in PIP channels play a crucial role in determining the pH at which water transport through these channels is blocked, highlighting the relevance of the differentially conserved very last residues in PIP1 and PIP2 paralogues.

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Two aquaporins, multiple ways of assembly

Cited by 6 publications

References 8 publications

AQP8 and AQP9 expression in patients with polycystic ovary syndrome and its association with in vitro fertilization‑embryo transfer outcomes

AQP8 and AQP9 expression in patients with polycystic ovary syndrome and its association with in vitro fertilization‑embryo transfer outcomes

Cooperativity in proton sensing by PIP aquaporins

PIP aquaporin pH‐sensing is regulated by the length and charge of the C‐terminal region

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