Analysis of partner of inscuteable, a Novel Player of Drosophila Asymmetric Divisions, Reveals Two Distinct Steps in Inscuteable Apical Localization

Yu, Fengwei; Morin, Xavier; Cai, Yu; Yang, Xiaohang; Chia, William

doi:10.1016/s0092-8674(00)80676-5

Cited by 351 publications

(382 citation statements)

References 56 publications

Supporting

Mentioning

363

Contrasting

Unclassified

Order By: Relevance

“…For larval brain immunofluorescence stainings, larvae were dissected in PBS and fixed for 20 min in 4% formaldehyde, and processed similar to embryo stainings as described (Yu et al 2000). Antibodies used were rabbit anti-Insc (1:1000), mouse anti-Mira (1:50, F. Matsuzaki), guinea pig anti-Dpn (1:1000, J. Skeath), mouse anti-Worniu (1:500), rabbit anti-phospho-Histone H3 (1:1000, Sigma), rat anti-Elav (1:10, DSHB), mouse antiCycE (1:10, H. Richadson), mouse anti-dMyc (1:5, B. Edgar), rabbit anti-AurA (1:100, D. Glover), mouse anti-Pros (1:10, DSHB), rabbit anti-Brat (1:100, J. Knoblich), rat anti-Brat (1:100, R.P.…”

Section: Immunohistochemistrymentioning

confidence: 99%

“…During NB asymmetric divisions, the mitotic spindle is oriented along an axis perpendicular to the epithelial layer and an asymmetric spindle is generated to give rise to two unequal-sized daughter cells with distinct cell fates. NB asymmetric divisions are controlled by an apically localized complex of proteins that include the Drosophila homologs of the conserved Par3 (Bazooka, Baz)/Par6 (DmPar6)/atypical protein kinase C(DaPKC) proteins (Kuchinke et al 1998;Wodarz et al 2000;Petronczki and Knoblich 2001), Inscuteable (Insc) (Kraut et al 1996), and heterotrimeric G proteins G␣i (Schaefer et al 2001;Yu et al 2003) and their regulators Partner of Insc (Pins) (Yu et al 2000), Locomotion defects (Loco) , and a Pins-interacting protein mushroom body defective (Mud) (Bowman et al 2006;Izumi et al 2006;Siller et al 2006). The asymmetric localization of G␣i requires G␤ (Schaefer et al 2001;Yu et al 2003) and G␥ (Fuse et al 2003) and its membrane localization requires Ric-8 (Hampoelz et al 2005;Wang et al 2005).…”

mentioning

confidence: 99%

See 1 more Smart Citation

Aurora-A acts as a tumor suppressor and regulates self-renewal of Drosophila neuroblasts

Wang¹,

Somers²,

Bashirullah³

et al. 2006

Genes Dev.

Self Cite

246

294

View full text Add to dashboard Cite

The choice of self-renewal versus differentiation is a fundamental issue in stem cell and cancer biology. Neural progenitors of the Drosophila post-embryonic brain, larval neuroblasts (NBs), divide asymmetrically in a stem cell-like fashion to generate a self-renewing NB and a Ganglion Mother Cell (GMC), which divides terminally to produce two differentiating neuronal/glial daughters. Here we show that Aurora-A (AurA) acts as a tumor suppressor by suppressing NB self-renewal and promoting neuronal differentiation. In aurA loss-of-function mutants, supernumerary NBs are produced at the expense of neurons. AurA suppresses tumor formation by asymmetrically localizing atypical protein kinase C (aPKC), an NB proliferation factor. Numb, which also acts as a tumor suppressor in larval brains, is a major downstream target of AurA and aPKC. Notch activity is up-regulated in aurA and numb larval brains, and Notch signaling is necessary and sufficient to promote NB self-renewal and suppress differentiation in larval brains. Our data suggest that AurA, aPKC, Numb, and Notch function in a pathway that involved a series of negative genetic interactions. We have identified a novel mechanism for controlling the balance between self-renewal and neuronal differentiation during the asymmetric division of Drosophila larval NBs.[Keywords: Neuroblast; stem cells; asymmetric division; tumor suppressor; self-renewal] Supplemental material is available at http://www.genesdev.org.

show abstract

Section: Immunohistochemistrymentioning

confidence: 99%

mentioning

confidence: 99%

Aurora-A acts as a tumor suppressor and regulates self-renewal of Drosophila neuroblasts

Wang¹,

Somers²,

Bashirullah³

et al. 2006

Genes Dev.

Self Cite

246

294

View full text Add to dashboard Cite

show abstract

“…For instance, Inscuteable is essential for asymmetric Numb localiza-2 S. S.-C. Li, unpublished data. tion to the basal cortex in mitotic neuroblasts (13,48). Interestingly, Inscuteable itself is localized to the apical membrane, an event that is dependent on Bazooka, the Drosophila homologue of Caenorhabditis elegans Par-3 (49).…”

Section: Nip Is a Membrane Anchor Formentioning

confidence: 99%

A Novel Transmembrane Protein Recruits Numb to the Plasma Membrane during Asymmetric Cell Division

Qin

Percival‐Smith

Liu

et al. 2004

Journal of Biological Chemistry

View full text Add to dashboard Cite

Numb, an evolutionarily conserved cell fate-determining factor, plays a pivotal role in the development of Drosophila and vertebrate nervous systems. Despite lacking a transmembrane segment, Numb is associated with the cell membrane during the asymmetric cell division of Drosophila neural precursor cells and is selectively partitioned to one of the two progeny cells from a binary cell division. Numb contains an N-terminal phosphotyrosine-binding (PTB) domain that is essential for both the asymmetric localization and the fate specification function of Numb. We report here the isolation and characterization of a novel PTB domain-binding protein, NIP (Numb-interacting protein). NIP is a multipass transmembrane protein that contains two PTB domainbinding, NXXF motifs required for the interaction with Numb. In dividing Drosophila neuroblasts, NIP is colocalized to the cell membrane with Numb in a basal cortical crescent. Expression of NIP in Cos-7 cells recruited Numb from the cytosol to the plasma membrane. This recruitment of Numb to membrane by NIP was dependent on the presence of at least one NXXF site. In Drosophila Schneider 2 cells, NIP and Numb were colocalized at the plasma membrane. Inhibition of NIP expression by RNA interference released Numb to the cytosol. These results suggest that a direct protein-protein interaction between NIP and Numb is necessary and sufficient for the recruitment of Numb to the plasma membrane. Recruitment of Numb to a basal cortical crescent in a dividing neuroblast is essential for Numb to function as an intrinsic cell fate determinant.Asymmetric cell division, which can involve extrinsic and/or intrinsic factors, is a fundamental mechanism of generating cell diversity during the development of complex organisms (1, 2). Extrinsic factors such as Delta and its receptor Notch (3, 4) function in cell-cell communication to specify the fate of cells (5-7). Asymmetric determinants are intrinsic factors that are selectively segregated into one of the two daughter cells when a cell divides (2,8). Consequently, the sibling cell that inherits the asymmetric determinants adopts a different fate from the one that does not. Numb is a member of a growing family of proteins that also includes Prospero, Miranda, Inscuteable, and PON (partner of numb) (9 -14), which act as intrinsic determinants in asymmetric cell division. These proteins were identified through their requirement in the development of Drosophila peripheral and central nervous systems. The external sensory organ in Drosophila is composed of two outer (hair and socket) cells and three inner (sheath, glial, and neuron) cells, which are derived from a single sensory organ precursor through three consecutive asymmetric cell divisions. Numb is selectively partitioned to one of the two daughter cells at each binary division (15). Numb is also required for the development of the central nervous system (16 -18). During delaminating from the neuroectoderm and asymmetric division of a neuroblast, Numb, Prospero, and several other proteins...

show abstract

“…In metaphase neuroblasts, Pins is colocalized at the apical cortex with the heterotrimeric G protein subunit G␣i and the spindle-associated, coiled-coil mushroom body defect protein (8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)) (Mud; NuMA in mammals, Lin-5 in C. elegans). Pins and G␣i are interdependent for localization and for establishing cortical polarity (17,18).…”

mentioning

confidence: 99%

Gαi generates multiple Pins activation states to link cortical polarity and spindle orientation in Drosophila neuroblasts

Nipper

Siller

Smith

et al. 2007

Proc. Natl. Acad. Sci. U.S.A.

108

View full text Add to dashboard Cite

Drosophila neuroblasts divide asymmetrically by aligning their mitotic spindle with cortical cell polarity to generate distinct sibling cell types. Neuroblasts asymmetrically localize G␣i, Pins, and Mud proteins; Pins/G␣i direct cortical polarity, whereas Mud is required for spindle orientation. It is currently unknown how G␣i-Pins-Mud binding is regulated to link cortical polarity with spindle orientation. Here, we show that Pins forms a ''closed'' state via intramolecular GoLoco-tetratricopeptide repeat (TPR) interactions, which regulate Mud binding. Biochemical, genetic, and live imaging experiments show that G␣i binds to the first of three Pins GoLoco motifs to recruit Pins to the apical cortex without ''opening'' Pins or recruiting Mud. However, G␣i and Mud bind cooperatively to the Pins GoLocos 2/3 and tetratricopeptide repeat domains, respectively, thereby restricting Pins-Mud interaction to the apical cortex and fixing spindle orientation. We conclude that Pins has multiple activity states that generate cortical polarity and link it with mitotic spindle orientation.cell polarity ͉ cell signaling ͉ differentiation ͉ protein-protein interactions I n complex, multicellular organisms, differentiated cell types are needed to perform diverse functions. One common mechanism for cellular differentiation is asymmetric cell division, in which the mitotic spindle is aligned with the cell polarity axis to generate molecularly distinct sibling cells (1-4). Asymmetric divisions have been proposed to regulate stem cell pool size during development, adult tissue homeostasis, and the uncontrolled proliferation observed in cancer (5). Thus, understanding how the mitotic spindle is coupled to the cell polarity axis is relevant to stem cell and cancer biology. Here, we investigate this question in Drosophila neuroblasts, a model system for studying asymmetric cell division.Drosophila neuroblasts are stem cell-like progenitors that divide asymmetrically to produce a larger self-renewing neuroblast and a smaller ganglion mother cell (GMC) that differentiates into neurons or glia (3). Mitotic neuroblasts segregate factors that promote neuroblast self-renewal to their apical cortex and differentiation factors to their basal cortex. Precise alignment of the mitotic spindle with the neuroblast apical/basal polarity is required for asymmetric cell division and proper brain development: spindle misalignment leads to symmetric cell divisions that expand the neuroblast population and brain size (6-8).

show abstract

Analysis of partner of inscuteable, a Novel Player of Drosophila Asymmetric Divisions, Reveals Two Distinct Steps in Inscuteable Apical Localization

Cited by 351 publications

References 56 publications

Aurora-A acts as a tumor suppressor and regulates self-renewal of Drosophila neuroblasts

Aurora-A acts as a tumor suppressor and regulates self-renewal of Drosophila neuroblasts

A Novel Transmembrane Protein Recruits Numb to the Plasma Membrane during Asymmetric Cell Division

Gαi generates multiple Pins activation states to link cortical polarity and spindle orientation in Drosophila neuroblasts

Contact Info

Product

Resources

About