Identifying the localization and exploring a functional role for Gprc5c in the kidney

Rajkumar, Premraj; Cha, Boyoung; Yin, Jianyi; Arend, Lois J.; Păunescu, Teodor G.; Hirabayashi, Yoshio; Donowitz, Mark; Pluznick, Jennifer L.

doi:10.1096/fj.201700610rr

Cited by 23 publications

(20 citation statements)

References 63 publications

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“…One of the proteins detected, GPRC5C (G protein‐coupled receptor class C group 5 member C), was detected only in the apical sample. GPRC5C is an orphan receptor that belongs to the GPRC5 family (Robbins et al, 2000) and is involved in renal acid–base homeostasis (Rajkumar et al, 2018), but it had never been reported as an exosome protein. GPRC5C was detected in the apical PEG pellet alone (Fig 2C) and floated into Fr.…”

Section: Resultsmentioning

confidence: 99%

ALIX and ceramide differentially control polarized small extracellular vesicle release from epithelial cells

et al. 2021

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Exosomes, important players in cell-cell communication, are small extracellular vesicles of endocytic origin. Although single cells are known to release various kinds of exosomes (referred to as exosomal heterogeneity), very little is known about the mechanisms by which they are produced and released. Here, we established methods of studying exosomal heterogeneity by using polarized epithelial cells and showed that distinct types of small extracellular vesicles (more specifically CD9-and CD63-positive, Annexin I-negative small extracellular vesicles, which we refer to as exosomes herein) are differentially secreted from the apical and basolateral sides of polarized epithelial cells. We also identify GPRC5C (G protein-coupled receptor class C group 5 member C) as an apical exosome-specific protein. We further demonstrate that basolateral exosome release depends on ceramide, whereas ALIX, an ESCRT (endosomal sorting complexes required for transport)-related protein, not the ESCRT machinery itself, is required for apical exosome release. Thus, two independent machineries, the ALIX-Syntenin1-Syndecan1 machinery (apical side) and the sphingomyelinase-dependent ceramide production machinery (basolateral side), are likely to be responsible for the polarized exosome release from epithelial cells.

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Section: Resultsmentioning

confidence: 99%

ALIX and ceramide differentially control polarized small extracellular vesicle release from epithelial cells

et al. 2021

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“…Using a TaqMan GPCR array card, we initially identified Gprc5c as being highly expressed in the murine kidney (17). Recently, we investigated further to identify the localization and physiological role of Gprc5c in the kidney (18). As determined by both immunohistochemistry and X-gal staining, Gprc5c localizes specifically to the apical membrane of renal proximal tubules of mice.…”

Section: Gpcr Family C Group 5 Member Cmentioning

confidence: 99%

Acid-base regulation in the renal proximal tubules: using novel pH sensors to maintain homeostasis

Rajkumar

Pluznick

2018

American Journal of Physiology-Renal Physiology

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The kidneys play a critical role in precisely regulating the composition of the plasma to maintain homeostasis. To achieve this, the kidneys must be able to accurately determine or "sense" the concentration of a wide variety of substances, and to make adjustments accordingly. Kidneys face a key challenge in the arena of pH balance, as there is a particularly narrow range over which plasma pH varies in a healthy subject (7.35-7.45), and this pH must constantly be protected against a variety of onslaughts (changes in diet, activity, and even elevation). The proximal tubule, the first segment to come into contact with the forming urine, plays an important role in helping the kidneys to maintain pH homeostasis. Recent studies have identified a number of novel proximal tubule proteins and signaling pathways which work to sense changes in pH, and subsequently modulate renal pH regulation. In this review, we will highlight the role of novel players in acid-base homeostasis in the proximal tubule.

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“…Gprc5c KO mice have reduced blood pH and elevated urine pH. 26 expression, highly expressed in health, is significantly reduced only two weeks following 5/6Nx in rats. 28,29 Our immunohistochemistry analysis of NHE3 expression ( Figure 2C) is consistent with these previous studies.…”

Section: Discussionmentioning

confidence: 99%

Functionally Essential Tubular Proteins Are Lost to Urine-Excreted, Large Extracellular Vesicles during Chronic Renal Insufficiency

et al. 2020

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BackgroundThe 5/6 nephrectomy (5/6Nx) rat model recapitulates many elements of human CKD. Within weeks of surgery, 5/6Nx rats spontaneously exhibit proximal tubular damage, including the production of very large extracellular vesicles and brush border shedding. We hypothesized that production and elimination of these structures, termed large renal tubular extracellular vesicles (LRT-EVs), into the urine represents a pathologic mechanism by which essential tubule proteins are lost.MethodsLRT-EVs were isolated from 5/6Nx rat urine 10 weeks after surgery. LRT-EV diameters were measured. LRT-EV proteomic analysis was performed by tandem mass spectrometry. Data are available via the ProteomeXchange Consortium with identifier PXD019207. Kidney tissue pathology was evaluated by trichrome staining, TUNEL staining, and immunohistochemistry.ResultsLRT-EV size and a lack of TUNEL staining in 5/6Nx rats suggest LRT-EVs to be distinct from exosomes, microvesicles, and apoptotic bodies. LRT-EVs contained many proximal tubule proteins that, upon disruption, are known to contribute to CKD pathologic hallmarks. Select proteins included aquaporin 1, 16 members of the solute carrier family, basolateral Na+/K+-ATPase subunit ATP1A1, megalin, cubilin, and sodium-glucose cotransporters (SLC5A1 and SLC5A2). Histologic analysis confirmed the presence of apical membrane proteins in LRT-EVs and brush border loss in 5/6Nx rats.ConclusionsThis study provides comprehensive proteomic analysis of a previously unreported category of extracellular vesicles associated with chronic renal stress. Because LRT-EVs contain proteins responsible for essential renal functions known to be compromised in CKD, their formation and excretion may represent an underappreciated pathogenic mechanism.

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Identifying the localization and exploring a functional role for Gprc5c in the kidney

Cited by 23 publications

References 63 publications

ALIX and ceramide differentially control polarized small extracellular vesicle release from epithelial cells

ALIX and ceramide differentially control polarized small extracellular vesicle release from epithelial cells

Acid-base regulation in the renal proximal tubules: using novel pH sensors to maintain homeostasis

Functionally Essential Tubular Proteins Are Lost to Urine-Excreted, Large Extracellular Vesicles during Chronic Renal Insufficiency

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