Interaction between the mammalian cell polarity proteins mInsc (mammalian homologue of Inscuteable) and Leu-Gly-Asn repeat-enriched protein (LGN), as well that their respective Drosophila homologues Inscuteable Partner (Pins), plays crucial roles in mitotic spindle orientation, a process contributing to asymmetric division. Here, we report crystal structure LGN-binding domain (LBD) human complexed with N-terminal tetratricopeptide repeat (TPR) motifs LGN at 2.6-Å resolution. In complex,...

Highlights•mInsc regulates directional movement during neutrophil chemotaxis•Chemoattractants induced Gαi-GDP accumulation at the front of migrating neutrophils•Gαi-GDP interacts with mInsc via LGN/AGS3 to recruit Par-aPKC complex•Both and aPKC are required for control, but not cell motilitySummarySuccessful chemotaxis requires only increased motility also sustained directionality. Here, we show that, receptors coupled Gi family heterotrimeric G proteins, is regulated by mInsc, a mammalian...

The membrane-integrated NADPH oxidases DUOX1 and DUOX2 are recruited to the apical plasma membrane in epithelial cells release hydrogen peroxide, thereby playing crucial roles various functions such as thyroid hormone synthesis host defense. However, it has remained unknown about molecular mechanism for sorting of DUOX2. Here we show that correctly sorted via membrane-spanning DUOX maturation proteins DUOXA1 DUOXA2, respectively, when co-expressed MDCK cells. Impairment N-glycosylation...

ABSTRACT The small GTPases RhoA and Cdc42 their effector proteins play crucial roles in neutrophil chemotaxis. However, endogenous localization regulation of these have remained largely unknown. Here, we show, using a trichloroacetic acid fixation method, that are preferentially accumulated at the F‐actin‐rich leading edge (pseudopod) during chemotaxis human neutrophil‐like PLB‐985 cells response to chemoattractant C5a. Interestingly, enrichment is impaired by knockdown Cdc42, indicating...

Formation of apico-basal polarity in epithelial cells is crucial for both morphogenesis (e.g., cyst formation) and function tight junction development). Atypical protein kinase C (aPKC), complexed with Par6, considered to translocate the apical membrane cell polarization. However, mechanism translocation Par6-aPKC complex has remained largely unknown. Here, we show that WD40 Morg1 (mitogen-activated organizer 1) directly binds Par6 thus facilitates targeting Madin-Darby canine kidney cells....

The adhesion family of G protein-coupled receptors (GPCRs) is defined by an N-terminal large extracellular region that contains various adhesion-related domains and a highly-conserved GPCR-autoproteolysis-inducing (GAIN) domain, the latter which located immediately before canonical seven-transmembrane domain. These are expressed widely involved in functions including development, angiogenesis, synapse formation, tumorigenesis. GPR125 (ADGRA3), orphan GPCR, has been shown to modulate planar...

Bipolar spindle assembly in mitotic cells is a prerequisite to ensure correct alignment of chromosomes for their segregation each daughter cell; microtubules are tethered at plus ends and focused minus either the two poles. NuMA (nuclear apparatus protein) present solely nucleus interphase cells, but relocalizes during mitosis poles play crucial role via focusing pole. In study we show that kinesin-5 family motor Eg5 protein directly interacts with NuMA, using proteomics approach various...

Proper mitotic spindle orientation requires that astral microtubules are connected to the cell cortex by microtubule-binding protein NuMA, which is recruited from cytoplasm. Cortical recruitment of NuMA at least partially mediated via direct binding adaptor LGN. LGN normally adopts a closed conformation an intramolecular interaction between its N-terminal NuMA-binding domain and C-terminal region contains four GoLoco (GL) motifs, each capable membrane-anchored Gαi subunit heterotrimeric G...

Correct cyst morphogenesis of epithelial cells requires apical–basal polarization, which is partly regulated by mitotic spindle orientation, a process dependent on the heterotrimeric G protein subunit Gαi and its binding LGN. Here, we show that in three‐dimensional culture mammalian Madin–Darby canine kidney (MDCK) cells, Gαi‐activating Ric‐8A crucial for orientation formation normal cysts comprise single layer polarized with their apical surfaces lining an inner lumen. Consistent...

A single epithelial cell embedded in extracellular matrix (ECM) can proliferate to form an apical lumen-harboring cyst, whose formation is a fundamental step organ development. At early two-cell stage after division, the doublet typically displays "inverted" polarity, with and basolateral proteins being located ECM-facing cell-cell-contacting plasma membranes, respectively. Correct cystogenesis requires polarity reorientation, process containing protein endocytosis from ECM-abutting...

Transmembrane glycoproteins, synthesized at the endoplasmic reticulum (ER), generally reach Golgi apparatus in COPII‐coated vesicles en route to cell surface. Here, we show that bona fide nonglycoprotein Nox5, a transmembrane superoxide‐producing NADPH oxidase, is transported surface manner resistant co‐expression of Sar1 (H79G), GTP‐fixed mutant small GTPase Sar1, which blocks COPII vesicle fission from ER. In contrast, (H79G) effectively inhibits ER‐to‐Golgi transport glycoproteins...

Abstract The tight junction (TJ) in epithelial cells is formed by integral membrane proteins and cytoplasmic scaffolding proteins. former contains the claudin family with four transmembrane segments, while latter includes Par3, a PDZ domain-containing adaptor that organizes TJ formation. Here we show single membrane-spanning protein TMEM25 localizes to TJs binds Par3 via PDZ-mediated interaction its C-terminal tail. development during cell polarization accelerated depletion of TMEM25,...

Tubulin acetylation by the enzyme αTAT1 regulates microtublules that participate in various events including cell division and cellular transport. Here we show quantity control of its cofactor (acetyl-CoA CoA)-mediated stabilization molecular mechanism for substrate recognition

Hepatocytes differ from columnar epithelial cells by their multipolar organization, which follows the initial formation of central lumen-sharing clusters polarized as observed during liver development and regeneration. The molecular mechanism for hepatocyte polarity establishment, however, has been comparatively less studied than those other cell types. Here, we show that tight junction protein Par3 organizes polarization via cooperating with small GTPase Cdc42 to target atypical kinase C...

Abstract The hydrogen peroxide (H 2 O )‐producing NADPH oxidase Nox4, forming a heterodimer with p22 phox , is expressed in variety of cells including those the heart to mediate adaptive responses cellular stresses such as hypoxia. Since Nox4 constitutively active, H production controlled by its protein abundance. Hypoxia‐induced expression observed various types and generally thought be regulated at transcriptional level. Here we show that hypoxia upregulates level Nox4‐catalyzed without...