Akt Regulates a Rab11-Effector Switch Required for Ciliogenesis

Walia, Vijay; Cuenca, Adrian; Vetter, Melanie; Insinna, Christine; Perera, Sumeth; Lu, Qiumin; Ritt, Daniel A.; Semler, Elizabeth M.; Specht, Suzanne I.; Stauffer, Jimmy K.; Morrison, Deborah K.; Lorentzen, Esben; Westlake, Christopher J.

doi:10.1016/j.devcel.2019.05.022

Cited by 54 publications

(74 citation statements)

References 47 publications

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“…Three other hits corresponded to previously reported Akt substrates namely BRISC And BRCA1 A Complex Member-1 (BABAM1/ MERIT40) (Ser29, PS1) [38], Ataxin-1 (Ser775, PS1) [39] and WDR44 (Ser344, PS1) [40]. The evidence that WDR44 is phosphorylated by Akt is based on biochemical analysis showing that immunoprecipitated Akt phosphorylated WDR44 at Ser342 and Ser344 [40]. However, mass spectrometry analysis we have undertaken suggest Ser344 which lies in an RXRXXS/T motif is the likely site of phosphorylation (>95% confidence) ( Fig 2C, Supplementary Excel file).…”

Section: Phosphoproteomic Screens To Identify Novel Sgk3 Substratessupporting

confidence: 80%

“…The proteomic screens also identified the previously characterized Akt and SGK NDRG1 substrate (Ser366, PS1) and (Ser326, PS2) as well as the related NDRG3 protein (Ser331, PS1). Three other hits corresponded to previously reported Akt substrates namely BRISC And BRCA1 A Complex Member-1 (BABAM1/ MERIT40) (Ser29, PS1) [38], Ataxin-1 (Ser775, PS1) [39] and WDR44 (Ser344, PS1) [40]. The evidence that WDR44 is phosphorylated by Akt is based on biochemical analysis showing that immunoprecipitated Akt phosphorylated WDR44 at Ser342 and Ser344 [40].…”

Section: Phosphoproteomic Screens To Identify Novel Sgk3 Substratessupporting

confidence: 78%

“…Recently, it has been reported that Akt can phosphorylate WDR44 at Ser342 and Ser344 and this phosphorylation enhances WDR44 binding to Rab11 and ultimately inhibits ciliogenesis [40]. Our data indicate that Ser344 is the phosphorylation site as mutation of Ser344 to Ala blocked phosphorylation of WDR44 ( Fig 3D).…”

Section: Discussionsupporting

confidence: 64%

“…It is likely that many of the SGK3 substrates identified in PS1 and PS2 will also comprise Akt substrates. Indeed, five out of 26 substrates identified in PS1, have previously been reported as Akt substrates namely ATXN1 [39], BABA1/Merit40 [38], NDRG1 [10], NEDD4L [28] and WDR44 [40]. Furthermore, six out of the 10 substrates that were tested namely NDRG1, MST1, PANK4, ITSN1, ATXN1 and AFF4 were similarly phosphorylated in vitro by both Akt and SGK3.…”

Section: Discussionmentioning

confidence: 88%

“…We also observed that Akt phosphorylated WDR44 in vitro to a much lesser extent than SGK3 and it would thus be interesting to explore whether SGK3 mediated phosphorylation of WDR44 could control Rab11 and ciliogenesis . As phosphorylation of WDR44 by SGK3 and by Akt in previous work [40], has thus far only been studied in vitro, it would be important to generate a phospho-specific antibody that recognizes WDR44 phosphorylation at 344 to better study whether it is phosphorylated in vivo by Akt and/or SGK isoforms.…”

Section: Discussionmentioning

confidence: 99%

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Phosphoproteomics reveals that the hVPS34 regulated SGK3 kinase specifically phosphorylates endosomal proteins including Syntaxin-7, Syntaxin-12, RFIP4 and WDR44

Malik

Nirujogi

Peltier

et al. 2019

Preprint

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The serum-and glucocorticoid-regulated kinase (SGK) isoforms contribute resistance to cancer therapies targeting the PI3K pathway. SGKs are homologous to Akt and these kinases display overlapping specificity and phosphorylate several substrates at the same residues, such as TSC2 to promote tumor growth by switching on the mTORC1 pathway. The SGK3 isoform is upregulated in breast cancer cells treated with PI3K or Akt inhibitors and recruited and activated at endosomes, through its phox homology domain binding to PtdIns(3)P. We undertook genetic and pharmacological phosphoproteomic screens to uncover novel SGK3 substrates. We identified 40 potential novel SGK3 substrates, including 4 endosomal proteins STX7 (Ser126) and STX12 (Ser139), RFIP4 (Ser527) and WDR44 (Ser346) that were efficiently phosphorylated in vitro by SGK3 at the sites identified in vivo, but poorly by Akt. We demonstrate that these substrates are poorly phosphorylated by Akt as they possess an n+1 residue from the phosphorylation site that is unfavorable for Akt phosphorylation. Phos-tag analysis revealed that stimulation of HEK293 cells with IGF1 to activate SGK3, promoted phosphorylation of a significant fraction of endogenous STX7 and STX12, in a manner that was blocked by knock-out of SGK3 or treatment with 14H inhibitor. SGK3 phosphorylation of STX12 enhanced interaction with the VAMP4/VTI1A/STX6 containing SNARE complex and promoted plasma membrane localization. Our data reveal novel substrates for SGK3 and suggest a mechanism by which STX7 and STX12 SNARE complexes are regulated by SGK3. They reveal new biomarkers for monitoring SGK3 pathway activity.

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Section: Phosphoproteomic Screens To Identify Novel Sgk3 Substratessupporting

confidence: 80%

Section: Phosphoproteomic Screens To Identify Novel Sgk3 Substratessupporting

confidence: 78%

Section: Discussionsupporting

confidence: 64%

Section: Discussionmentioning

confidence: 88%

Section: Discussionmentioning

confidence: 99%

See 3 more Smart Citations

Phosphoproteomics reveals that the hVPS34 regulated SGK3 kinase specifically phosphorylates endosomal proteins including Syntaxin-7, Syntaxin-12, RFIP4 and WDR44

Malik

Nirujogi

Peltier

et al. 2019

Preprint

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WDR44 Loss‐of‐Function Promoter Deletion in a Male Newborn With a Ciliopathy Phenotype

Sneddon,

Gilmore,

Xiong

et al. 2024

American J of Med Genetics Pt A

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Gain‐of‐function variants in the WDR44 gene have recently been associated with an X‐linked ciliopathy‐related neurodevelopmental phenotype. Here, we report on a WDR44 loss‐of‐function (LOF) variant identified in the genome sequence from a male fetus enrolled in the Prenatal Genetic Diagnosis by Genomic Sequencing (PrenatalSEQ) multicenter study. The phenotype is consistent with the described X‐linked ciliopathy that includes developmental delay, microcephaly, congenital heart defects, kidney abnormalities, cryptorchidism, musculoskeletal abnormalities, craniofacial dysmorphism, and effusions. This is the first report of a WDR44 LOF variant in an affected individual with a prenatal presentation and supports LOF as a mechanism for the X‐linked WDR44 ciliopathy‐related phenotype.

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