PKC Phosphorylation Increases the Ability of AFAP-110 to Cross-link Actin Filaments

Qian, Yong; Baisden, Joseph M.; Cherezova, Lidia; Summy, Justin M.; Guappone-Koay, Anne; Shi, Xianglin; Mast, Tom; Pustula, Jennifer; Zot, Henry G.; Mazloum, Nayef; Lee, Marietta Y.; Flynn, Daniel C.

doi:10.1091/mbc.e01-12-0148

Cited by 40 publications

(94 citation statements)

References 43 publications

(76 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…These data suggest that, as early as the 2-4 cell stages, the blastomeres could have prepared differently for future asymmetric divisions. Consistent with this idea, bimodal Afap1 encodes a protein that interacts with atypical protein kinase C (aPKC) (Qian et al 2002), which adopt polarized localization from the 8-cell stage onward and regulate cell fate decisions (Plusa et al 2005a). In summary, these single-cell data from matched sister blastomeres argue against the equivalence hypothesis, and lead to several mechanistic insights into the proposed early asymmetry.…”

Section: Ega Is Implicated To the Creation Of Asymmetrymentioning

confidence: 90%

Cell fate inclination within 2-cell and 4-cell mouse embryos revealed by single-cell RNA sequencing

2014

View full text Add to dashboard Cite

It remains an open question when and how the first cell fate decision is made in mammals. Using deep single-cell RNA-seq of matched sister blastomeres, we report highly reproducible inter-blastomere differences among 10 2-cell and five 4-cell mouse embryos. Inter-blastomere gene expression differences dominated between-embryo differences and noise, and were sufficient to cluster sister blastomeres into distinct groups. Dozens of protein-coding genes exhibited reproducible bimodal expression in sister blastomeres, which cannot be explained by random fluctuations. The protein expression of one gene out of four of these bimodal genes tested, Gadd45a, exhibited clear inter-blastomeric contrasts. We traced some of the bimodal mRNA expressions to embryonic genome activation, and others to blastomere-specific RNA depletion. Interblastomere differences created coexpression gene networks that were much stronger and larger than those that can possibly be created by random noise. The highly correlated gene pairs at the 4-cell stage overlapped with those showing the same directions of differential expression between inner cell mass (ICM) and trophectoderm (TE). These data substantiate the hypothesis of inter-blastomere differences in 2-and 4-cell mouse embryos, and associate these differences with ICM/ TE differences.

show abstract

Section: Ega Is Implicated To the Creation Of Asymmetrymentioning

confidence: 90%

Cell fate inclination within 2-cell and 4-cell mouse embryos revealed by single-cell RNA sequencing

2014

View full text Add to dashboard Cite

show abstract

“…In principle, a receptor-mediated PKC-dependent increase in cortical F-actin density could be induced by the recruitment of F-actin into this subcellular compartment (Qian et al, 2002) or in response to an increase in the rate of local actin polymerization (Pilpel and Segal, 2004). However, the Ang IImediated increase in cortical F-actin density observed in MNCs was not accompanied by a concurrent decrease in the amount of F-actin in the cytoplasm (Fig.…”

Section: How Does Ang II Mediate An Increase In Cortical F Actin Densmentioning

confidence: 97%

Amplification of Transducer Gain by Angiotensin II-Mediated Enhancement of Cortical Actin Density in Osmosensory Neurons

Zhang¹,

Bourque²

2008

J. Neurosci.

View full text Add to dashboard Cite

Osmosensory neurons transduce osmotic signals into a neural spike code that commands behavioral and endocrine responses that mediate body fluid homeostasis. Although changes in osmoregulatory reflex gain are known to occur under physiological and pathological conditions, the basis for this modulation is unknown. Here, we show that angiotensin II amplifies osmosensory transduction by enhancing the proportional relationship between osmolality, receptor potential, and action potential firing in rat supraoptic nucleus neurons. This effect is mediated by a phospholipase C-and protein kinase C-dependent increase in cellular mechanosensitivity that is associated with a rapid increase in cortical actin filament density. Preventing this increase with cytochalasin D eliminated the enhancement of mechanosensitivity, whereas enhancing actin filament density with jasplakinolide potentiated mechanosensitivity and occluded the effects of angiotensin II. These results indicate that a receptor-mediated increase in cortical actin density can enhance osmosensitivity in acutely isolated supraoptic neurons.

show abstract

“…AFAP-110 is a binding partner for PKCα, a target of PKCα phosphorylation in vitro and becomes phosphorylated on Ser residues upon PE treatment in vivo (Qian et al, 2002). Here we show that treatment of GFP-AFAP-110-overexpressing cells treated with the PE phorbol-12-myristate-13-acetate (PMA) resulted in a gel shift of the AFAP-110 protein band in western blot analysis ( Fig.…”

Section: Pe Treatment Causes a Gel Shift Of The Afap-110 Protein Bandmentioning

confidence: 66%

“…Mutation of the proline residue at position 71 to Ala (P71A) within the SH3-binding motif abolishes Src binding to AFAP-110 and prevents AFAP-110 from directing Src activation. The N-terminal PH domain (PH1) was found to bind to the protein kinase C (PKC) α, β, γ and λ isoforms and, upon PKCα activation, AFAP-110 subsequently becomes phosphorylated on Ser/Thr residues (Qian et al, 2002;Qian et al, 2004). Phosphorylation of AFAP-110 will induce a conformational change that releases autoinhibitory intramolecular interactions and correlates with an acquired ability to activate Src, alter actin filament crosslinking and induce podosome formation .…”

Section: Afap-110 Is An Actin-binding and -Crosslinking Protein That mentioning

confidence: 99%

“…Gel shifts during SDS-PAGE can occur when a protein is phosphorylated, which prevents SDS from coating the protein efficiently, resulting in a slightly retarded migration to the cathode and a higher relative mass of the protein. Thus, because PMA is a wellknown activator of PKC family members such as PKCα (Kazanietz, 2000), and AFAP-110 is a substrate and binding partner for PKCα (Qian et al, 2002), we predicted that the resulting gel shift was associated with increased AFAP-110 phosphorylation on Ser/Thr residue(s). Previous studies have found that phosphorylation of AFAP-110 by recombinant PKCα can direct a conformational change in AFAP-110 (Qian et al, 2004).…”

Section: Pe Treatment Causes a Gel Shift Of The Afap-110 Protein Bandmentioning

confidence: 99%

See 1 more Smart Citation

Phosphorylation of AFAP-110 affects podosome lifespan in A7r5 cells

Dorfleutner

Cho

Vincent

et al. 2008

Journal of Cell Science

Self Cite

View full text Add to dashboard Cite

AFAP-110 is an actin-binding and -crosslinking protein that is enriched in Src and phorbol ester (PE)-induced podosomes. In vascular smooth muscle cells endogenous AFAP-110 localized to actin stress fibers and, in response to treatment with phorbol-12,13-dibutyrate (PDBu), to actin-rich podosomes. Since PEs can activate PKCα, AFAP-110 is a substrate of PKCα and PKCα–AFAP-110 interactions direct podosome formation, we sought to identify a PE-induced phosphorylation site in AFAP-110 and determine whether phosphorylation is linked to the formation of podosomes. Mutational analysis revealed Ser277 of AFAP-110 to be phosphorylated in PE-treated cells. The use of a newly generated, phospho-specific antibody directed against phosphorylated Ser277 revealed that PKCα activation is associated with PE-induced AFAP-110 phosphorylation. In PDBu-treated A7r5 rat vascular smooth muscle cells, immunolabeling using the phospho-specific antibody showed that phospho-AFAP-110 is primarily associated with actin in podosomes. Although mutation of Ser at position 277 to Ala (AFAP-110S277A) did not alter the ability of AFAP-110 to localize to podosomes, overexpression of AFAP-110S277A in treated and untreated A7r5 cells resulted in an increased number of cells that display podosomes. Video microscopy demonstrated that AFAP-110S277A expression correlates with an increased number of long-lived podosomes. Therefore, we hypothesize that AFAP-110 phosphorylation and/or dephosphorylation is involved in the regulation of podosome stability and lifespan.

show abstract

PKC Phosphorylation Increases the Ability of AFAP-110 to Cross-link Actin Filaments

Cited by 40 publications

References 43 publications

Cell fate inclination within 2-cell and 4-cell mouse embryos revealed by single-cell RNA sequencing

Cell fate inclination within 2-cell and 4-cell mouse embryos revealed by single-cell RNA sequencing

Amplification of Transducer Gain by Angiotensin II-Mediated Enhancement of Cortical Actin Density in Osmosensory Neurons

Phosphorylation of AFAP-110 affects podosome lifespan in A7r5 cells

Contact Info

Product

Resources

About