SGK3

This gene is a member of the Ser/Thr protein kinase family and encodes a phosphoprotein with a PX (phox homology) domain. The protein phosphorylates several target proteins and has a role in neutral amino acid transport and activation of potassium and chloride channels. Alternate transcriptional splice variants, encoding different isoforms, have been characterized. [provided by RefSeq, Jul 2008]

Full Name

Serum/Glucocorticoid Regulated Kinase Family Member 3

Function

Serine/threonine-protein kinase which is involved in the regulation of a wide variety of ion channels, membrane transporters, cell growth, proliferation, survival and migration. Up-regulates Na+ channels: SCNN1A/ENAC and SCN5A, K+ channels: KCNA3/KV1.3, KCNE1, KCNQ1 and KCNH2/HERG, epithelial Ca2+ channels: TRPV5 and TRPV6, chloride channel: BSND, creatine transporter: SLC6A8, Na+/dicarboxylate cotransporter: SLC13A2/NADC1, Na+-dependent phosphate cotransporter: SLC34A2/NAPI-2B, amino acid transporters: SLC1A5/ASCT2 and SLC6A19, glutamate transporters: SLC1A3/EAAT1, SLC1A6/EAAT4 and SLC1A7/EAAT5, glutamate receptors: GRIA1/GLUR1 and GRIK2/GLUR6, Na+/H+ exchanger: SLC9A3/NHE3, and the Na+/K+ ATPase. Plays a role in the regulation of renal tubular phosphate transport and bone density. Phosphorylates NEDD4L and GSK3B. Positively regulates ER transcription activity through phosphorylation of FLII. Negatively regulates the function of ITCH/AIP4 via its phosphorylation and thereby prevents CXCR4 from being efficiently sorted to lysosomes.

Biological Process

Intracellular signal transductionManual Assertion Based On ExperimentIBA:GO_Central
Peptidyl-serine phosphorylationManual Assertion Based On ExperimentIBA:GO_Central
Protein phosphorylationManual Assertion Based On ExperimentTAS:ProtInc
Regulation of cell growthManual Assertion Based On ExperimentTAS:UniProtKB
Regulation of cell migrationManual Assertion Based On ExperimentTAS:UniProtKB
Regulation of cell population proliferationManual Assertion Based On ExperimentTAS:UniProtKB
Regulation of DNA-binding transcription factor activityManual Assertion Based On ExperimentTAS:UniProtKB

Cellular Location

Cytoplasmic vesicle
Early endosome
Recycling endosome
Endosomal localization is a prerequisite for complete kinase activity. It is essential for its colocalization with the kinase responsible for phosphorylating Ser-486 thus allowing PDPK1 phosphorylation of Thr-320 resulting in complete activation of SGK3. Localized in vesicle-like structures and in the early endosome. Colocalizes with SLC9A3/NHE3 in the recycling endosomes.

PTM

Activated by phosphorylation on Ser-486 by an unknown kinase (may be mTORC2 but not confirmed), transforming it into a substrate for PDPK1 which then phosphorylates it on Thr-320.