Found in an ovualtion array.
NCBI Summary:
Potassium channels are present in most mammalian cells, where they participate in a wide range of physiologic responses. The protein encoded by this gene is an integral membrane protein and inward-rectifier type potassium channel. The encoded protein, which has a greater tendency to allow potassium to flow into a cell rather than out of a cell, is controlled by G-proteins. [provided by RefSeq]
General function
Channel/transport protein
Comment
Cellular localization
Plasma membrane
Comment
Ovarian function
Comment
Changes in granulosa cells gene expression associated with increased oocyte competence in bovine. Nivet AL et al. One of the challenges in mammalian reproduction is to understand basic physiology of oocyte quality. It is believed that the follicle status is linked to developmental competence of the enclosed oocyte. To explore the link between follicles and competence in cows, a previous experiment from our laboratory has developed an ovarian stimulation protocol that increases and then decreases oocyte quality according to the timing of oocyte recovery post FSH withdrawal (coasting). Using such protocol, we have obtained the granulosa cells associated with oocytes of different qualities at selected times of coasting. Transcriptome analysis was done with Embryogene microarray slides and validation by real-time PCR. Results shows that the major changes in gene expression occurred from 20h to 44h of coasting, when oocyte quality rising. Secondly, among up-regulated genes (20h to 44h), 25%were extracellular molecules, highlighting potential granulosa signaling cascades. Principal component analysis identified 2 patterns: one resembling the competence profile and another associated with follicle growth and atresia. Additionally, 3 major functional changes were identified: 1) the end of follicle growth (BMPR1B, IGF2, RELN), involving interactions with the extracellular matrix (TFPI2); angiogenesis (NRP1), including early hypoxia, and potentially oxidative stress (GFPT2, TF, VNN1) and 2) apoptosis (KCNJ8) followed by 3) inflammation (ANKRD1). This unique window of analysis indicates a progressive hypoxia during coasting mixed with an increase of apoptosis and inflammation. Potential signaling pathways leading to competence have been identified and will require downstream testing. This preliminary analysis supports the potential role of the follicular differentiation in oocyte quality both during competence increase and decrease phases.
Expression regulated by
Comment
Ovarian localization
Oocyte, Granulosa
Comment
Human oocytes express ATP-sensitive K+ channels. Du Q et al. BACKGROUND ATP-sensitive K(+) (K(ATP)) channels link intracellular metabolism with membrane excitability and play crucial roles in cellular physiology and protection. The K(ATP) channel protein complex is composed of pore forming, Kir6.x (Kir6.1 or Kir6.2) and regulatory, SURx (SUR2A, SUR2B or SUR1), subunits that associate in different combinations. The objective of this study was to determine whether mammalian oocytes (human, bovine, porcine) express K(ATP) channels. METHODS Supernumerary human oocytes at different stages of maturation were obtained from patients undergoing assisted conception treatments. Bovine and porcine oocytes in the germinal vesicle (GV) stage were obtained by aspirating antral follicles from abattoir-derived ovaries. The presence of mRNA for K(ATP) channel subunits was determined using real-time RT-PCR with primers specific for Kir6.2, Kir6.1, SUR1, SUR2A and SUR2B. To assess whether functional K(ATP) channels are present in human oocytes, traditional and perforated patch whole cell electrophysiology and immunoprecipitation/western blotting were used. RESULTS Real-time PCR revealed that mRNA for Kir6.1, Kir6.2, SUR2A and SUR2B, but not SUR1, were present in human oocytes of different stages. Only SUR2B and Kir6.2 mRNAs were detected in GV stage bovine and porcine oocytes. Immunoprecipitation with SUR2 antibody and western blotting with Kir6.1 antibody identified bands corresponding to these subunits in human oocytes. In human oocytes, 2,4-dinitrophenol (400 ?M), a metabolic inhibitor known to decrease intracellular ATP and activate K(ATP) channels, increased whole cell K(+) current. On the other hand, K(+) current induced by low intracellular ATP was inhibited by extracellular glibenclamide (30 ?M), an oral antidiabetic known to block the opening of K(ATP) channels. CONCLUSIONS In conclusion, mammalian oocytes express K(ATP) channels. This opens a new avenue of research into the complex relationship between metabolism and membrane excitability in oocytes under different conditions, including conception.