Phosphopeptides from proteins involved in regulation of actin cytoskeleton that are altered in abundance in response to dDAVP in rat IMCD suspensions* (See below for narrative)
*Peptides satisfied dual criteria: |Mean log2(dDAVP/Control)| > 0.342 and FDR < 0.005. The value 0.342 defines the 95% confidence interval for control:control comparisons.
§, Phosphorylated amino acid indicated by *; #, deamidated asparagine or glutamine; †, False Discovery Rate; ‡ Imported from "FUNCTION" field of UniProt record
| Gene Symbol |
UniProt no. |
Residue(s) |
Peptide§ |
Mean log2(dDAVP/Vehicle) |
SD log2(dDAVP/Vehicle) |
FDR† |
Function in regulation of actin cytoskeleton‡ |
Abi1,Q9QZM5,S291;T296,HNS*TTSST*SSGGYR,-0.641,0.230,9.97E-06,Involved in cytoskeletal reorganization and EGFR signaling. Together with EPS8 participates in transduction of signals from Ras to Rac.,
Abi1,Q9QZM5,S297;S298,HNST?TSSTS*S*GGYRR,-0.560,0.325,1.29E-04,Same as above.,
Ajuba,Q5U2Z2,S89,GS*FEAQR,0.733,0.048,3.97E-08,Contributes to the linking and/or strengthening of epithelia cell-cell junctions in part by linking adhesive receptors to the actin cytoskeleton.,
Akap13,F1M3G7,S770,GSS*FSLASSPESESVTK,0.661,0.203,4.69E-06,Activates RHOA in response to signaling via G protein-coupled receptors via its function as RhoGEF (PMID:23658642). Functions as scaffold protein that anchors cAMP-dependent protein kinase (PKA) and PRKD1.,
Arhgef1,Q9Z1I6,S301,GS*LGISSR,0.863,0.151,7.91E-09,"Role in the regulation of RhoA GTPase by guanine nucleotide-binding alpha-12 (GNA12) and alpha-13 (GNA13) subunits. Acts as GTPase-activating protein (GAP) for GNA12 and GNA13, and as guanine nucleotide exchange factor (GEF) for RhoA GTPase. ",
Arhgef2,Q5FVC2,S885,S*LPAGDALYLSFNPPQPSR,0.737,0.112,1.88E-07,"Activates Rho-GTPases. Phosphorylation of Ser-885 by PAK1 induces binding to protein YWHAZ, promoting its relocation to microtubules and the inhibition of its activity.",
Arhgef6,Q5XXR3,S680,KDS*VPQVLLPEEEK,0.725,0.121,3.09E-07,A RAC1 guanine nucleotide exchange factor (GEF). Interacts with PAK kinases through the SH3 domain. Interacts with BIN2.,
Arhgef7,O55043,S560,KES*APQVLLPEEEK,0.802,0.244,1.32E-07,RAC1 guanine nucleotide exchange factor (GEF). Functions in cell attachment and spreading. Promotes targeting of RAC1 to focal adhesions. Downstream of CaMKK-CaMK1 signaling cascade.,
Dstn,Q7M0E3,S24,C^S*TPEEIK,0.526,0.144,6.32E-05,Actin-depolymerizing protein. Severs actin filaments (F-actin) and binds to actin monomers (G-actin).,
Golph3,Q9ERE4,S9,SS*GLVQR,-0.538,0.312,2.01E-04,Interacts with MYO18A; the interaction is direct and may link Golgi membranes to the actin cytoskeleton.,
Kalrn,P97924,S1772,S*FDLGSPKPGDETTPQGDSADEK,1.267,0.190,3.19E-15,"Activates specific Rho GTPase family members, thereby inducing regulating cell shape, growth, and plasticity, through their effects on the actin cytoskeleton. The two GEF domains catalyze nucleotide exchange for Rac1 and RhoA.",
Kalrn,P97924,S1777,SFDLGS*PKPGDETTPQGDSADEK,-1.104,0.524,1.81E-11,Same as above.,
Mprip,Q9ERE6,S306,RS*QVIEK,0.674,0.205,3.44E-06,Targets myosin phosphatase to the actin cytoskeleton. Required for the regulation of the actin cytoskeleton by RhoA and ROCK1. Depletion leads to an increased number of stress fibers through stabilization of actin fibers by phosphorylated myosin. ,
Myo9b,Q63358,S1649,RKS*ELGAEPGHFGVC^VDSLTSDK,0.691,0.113,6.73E-07,Also acts as a GTPase activator for RHOA (PubMed:7882973). Interacts (via IQ domains) with calmodulin.,
Myo9b,Q63358,S1327,IS*FSTSDVSK,0.538,0.142,4.67E-05,Same as above.,
Pdlim5,Q62920,S228,GS*QGDIK,0.679,0.379,9.33E-06,Scaffold protein that interacts with various PKC isoforms through the LIM domains (PubMed:8940095). Interacts with actin and alpha-actinin through the PDZ domain (PubMed:10833443). Interacts (via LIM domains) with SIPA1L1.,
Phactr1,P62024,S67,SKS*DTPYLAEAR,0.968,0.469,2.19E-09,Binds actin monomers (G actin) and plays a role in the reorganization of the actin cytoskeleton and in formation of actin stress fibers. Regulates PPP1CA activity. ,
Phactr2,P62025,S168,ASSS*PSASSTSSHPR,-1.112,0.393,7.89E-12,Same as above. Binds PPP1CA and actin.,
Pip5k1a,D3ZSI8,S55,SVDS*SGETTYK,0.643,0.177,5.77E-06,"Catalyzes the phosphorylation of phosphatidylinositol 4-phosphate (PtdIns4P) to form phosphatidylinositol 4,5-bisphosphate (PtdIns(4,5)P2). Participates in a variety of cellular processes such as actin cytoskeleton organization and cell adhesion.",
Prkce,P09216,S329,LAAGAES*PQPASGNSPSEDDR,-0.726,0.192,7.43E-07,"Regulates of multiple cellular processes linked to cytoskeletal proteins, such as cell adhesion, motility. Phosphorylates IQGAP1 mediating epithelial cell-cell detachment prior to migration. Is indirectly associated with F-actin via interaction with COPB1.",
Ptpn21,Q62728,S670;S675; S676;S679,TFS*AGSQS*S*VFS*DKVK,0.647,0.045,3.46E-07,"Nonreceptor tyrosine phosphatase. FERM domain attaches to the plasma membrane by binding specific membrane proteins, while the last 34 residues bind actin filaments. Aside from binding to membranes, can also bind RhoGDI.",
Rflnb,Q6AXS9,S6,LS*LQDVPELVDTK,0.802,0.238,1.26E-07,Involved in the regulation of the perinuclear actin network and nuclear shape through interaction with filamins. ,
Snx1,Q99N27,S188,FS*DFLGLYEK,1.016,0.255,1.25E-10, Colocalized with F-actin at the leading edge of lamellipodia in a kalirin-dependent manner.,
Sptbn2,Q9QWN8,S2254,GS*LGFYK,2.129,0.323,3.16E-16,Links plasma membrane proteins to actin cytoskeleton.,
Src,Q9WUD9,S17,S*LEPAENVHGAGGAFPASQTPSKPASADGHR,0.639,0.060,7.57E-07,Role in the regulation of cytoskeletal organization. Phosphorylation of AFAP1 allows the SRC to bind AFAP1 and to localize to actin filaments. Cytoskeletal reorganization is also controlled through the phosphorylation of cortactin (CTTN).,
Washc2,Q80X08,S711;S720,KES*IPKVPLLFS*DEEDSEVPSGVKPVDLK,1.206,0.084,8.20E-15,Component of the WASH core complex at the surface of endosomes that activates the Arp2/3 complex to induce actin polymerization promoting fission of tubules during endosome sorting. ,
Vasopressin-mediated actin depolymerization and loss of stress fibers. Vasopressin triggers depolymerization of apical cortical actin [(Simon, 1993), (Klussman, 2001), (Tamma, 2001), (Loo, 2013)] as well as a loss of basal acto-myosin stress fibers [(Chou, 2004), (Isobe, 2017)] in the AQP2 expressing cells of the renal collecting duct (Figure 0). This response is mediated in part by PKA-mediated phosphorylation of RhoA (Tamma, 2001). It has been proposed that a dense cortical actin network is a barrier to exocytosis of AQP2-containing vesicles and the depolymerization is, therefore critical to the ability of vasopressin to increase the water permeability of the apical plasma membrane [(Tamma, 2001), (Noda, 2008), (Loo, 2013)]. The above table lists the relevant phosphopeptides altered in abundance in response to dDAVP in the present study. This includes several phosphopeptides that map to Rho and Rac GEFs which are likely to play roles in regulation of the actin cytoskeleton, most of which have been identified as PKA substrates (https://hpcwebapps.cit.nih.gov/ESBL/PKANetwork/Actin.html).
Twenty of 26 of the peptides in the above table were phosphorylated at sites with R or K in position -3, consistent with direct effects of PKA or other related basophilic protein kinases. PCTAIRE kinase 1/Cdk16 is of special interest. It has been proposed to trigger a Pak1-dependent kinase cascade that increases the actin-depolymerizing activity of cofilin (Mokalled, 2010). PCTAIRE kinase 3/Cdk18 has been proposed to play a similar role in regulation of the actin cytoskeleton (Matsuda, 2017).
