The Journal of Cell Biology recent issues

Niche recycling through division-independent egress of hematopoietic stem cells

Mon, 16 Nov 2009 10:11:50 PST

Transcellular migration of leukocytes is mediated by the endothelial lateral border recycling compartment

Mamdouh, Z., Mikhailov, A., Muller, W. A. — Mon, 16 Nov 2009 10:11:50 PST

Histone H2AX stabilizes broken DNA strands to suppress chromosome breaks and translocations during V(D)J recombination

Mon, 16 Nov 2009 10:11:50 PST

Cohesin pathway makes the necessary arrangements

Short, B. — Mon, 16 Nov 2009 10:11:49 PST

Germ cells decide for themselves

Short, B. — Mon, 16 Nov 2009 10:11:49 PST

Sizing up the ER stress response

Short, B. — Mon, 16 Nov 2009 10:11:49 PST

Adhering to the message

Short, B. — Mon, 16 Nov 2009 10:11:49 PST

How cell adhesion molecules transmit signals across the plasma membrane.

Michael Buszczak: Tracking the big game in stem cell identity

Sedwick, C. — Mon, 16 Nov 2009 10:11:49 PST

Buszczak is exploring the regulation of proteins that control stem cell identity in the fly.

Journeys through the Golgi--taking stock in a new era

Mon, 16 Nov 2009 10:11:49 PST

The Golgi apparatus is essential for protein sorting and transport. Many researchers have long been fascinated with the form and function of this organelle. Yet, despite decades of scrutiny, the mechanisms by which proteins are transported across the Golgi remain controversial. At a recent meeting, many prominent Golgi researchers assembled to critically evaluate the core issues in the field. This report presents the outcome of their discussions and highlights the key open questions that will help guide the field into a new era.

Cohesinopathy mutations disrupt the subnuclear organization of chromatin

Mon, 16 Nov 2009 10:11:50 PST

Nuclear morphology, chromosomal condensation, and transcriptional-mediated localization of genes to the nuclear periphery are disturbed by mutations in cohesin pathway genes.

A dual function for Pex3p in peroxisome formation and inheritance

Munck, J. M., Motley, A. M., Nuttall, J. M., Hettema, E. H. — Mon, 16 Nov 2009 10:11:50 PST

Pex3p interacts with peroxisome retention factor Inp1p at the peroxisomal membrane and functions in the organelle’s segregation in addition to its biogenesis.

Drosophila glypicans regulate the germline stem cell niche

Hayashi, Y., Kobayashi, S., Nakato, H. — Mon, 16 Nov 2009 10:11:50 PST

Heparan sulfate glycoproteins dally and dally-like define the germ cell niche in female and male Drosophila, respectively.

Quantitative analysis of chromatin compaction in living cells using FLIM-FRET

Lleres, D., James, J., Swift, S., Norman, D. G., Lamond, A. I. — Mon, 16 Nov 2009 10:11:50 PST

FRET analysis of cell lines expressing fluorescently tagged histones on separate nucleosomes demonstrates that variations in chromosome compaction occur during mitosis.

Lte1 contributes to Bfa1 localization rather than stimulating nucleotide exchange by Tem1

Geymonat, M., Spanos, A., de Bettignies, G., Sedgwick, S. G. — Mon, 16 Nov 2009 10:11:50 PST

Reevaluation of Lte1’s involvement in the mitotic exit network reveals that it is involved in localizing Bfa1 to the spindle pole body but does not function as a GEF for Tem1.

Capacity for stochastic self-renewal and differentiation in mammalian spermatogonial stem cells

Mon, 16 Nov 2009 10:11:50 PST

Spermatogonial stem cells have an innate ability to choose, with constant probability, between different fates independently of cues from the microenvironment.

Membrane expansion alleviates endoplasmic reticulum stress independently of the unfolded protein response

Schuck, S., Prinz, W. A., Thorn, K. S., Voss, C., Walter, P. — Mon, 16 Nov 2009 10:11:50 PST

Increasing the size of the ER by lipid synthesis helps the cell deal with ER stress.

Adenovirus RID-{alpha} activates an autonomous cholesterol regulatory mechanism that rescues defects linked to Niemann-Pick disease type C

Cianciola, N. L., Carlin, C. R. — Mon, 16 Nov 2009 10:11:50 PST

Viral subversion of cholesterol homeostasis provides insights into sterol trafficking, autophagy, and lysosomal storage diseases.

The CEACAM1 N-terminal Ig domain mediates cis- and trans-binding and is essential for allosteric rearrangements of CEACAM1 microclusters

Mon, 16 Nov 2009 10:11:50 PST

Structural analyses reveal that oligomerization between cell adhesion molecules in the same membrane is influenced by their interactions across opposing membranes (see also in this issue the accompanying paper by Müller et al.).

Homophilic adhesion and CEACAM1-S regulate dimerization of CEACAM1-L and recruitment of SHP-2 and c-Src

Muller, M. M., Klaile, E., Vorontsova, O., Singer, B. B., Obrink, B. — Mon, 16 Nov 2009 10:11:50 PST

The monomer/dimer equilibrium of adhesion molecule CEACAM1-L is regulated by binding between opposing membranes, which in turn controls cytoplasmic enzyme binding and signaling (see also in this issue the accompanying paper by Klaile et al.).

Runx proteins regulate Foxp3 expression

Mon, 02 Nov 2009 10:42:11 PST

Prospective identification, isolation, and systemic transplantation of multipotent mesenchymal stem cells in murine bone marrow

Mon, 02 Nov 2009 10:42:11 PST

Spermatozoa capture HIV-1 through heparan sulfate and efficiently transmit the virus to dendritic cells

Mon, 02 Nov 2009 10:42:11 PST

{gamma}-TuRC gives microtubules pause for thought

Short, B. — Mon, 02 Nov 2009 10:42:10 PST

Raf-1 sheds then spreads its inhibitions

Short, B. — Mon, 02 Nov 2009 10:42:10 PST

Chemosensitivity depends on the dependency

Short, B. — Mon, 02 Nov 2009 10:42:10 PST

Not the average view of adipogenesis

Short, B. — Mon, 02 Nov 2009 10:42:10 PST

Study on cell heterogeneity offers a surprising twist to adipocyte differentiation.

Irving Weissman: Working for regenerative medicine

LeBrasseur, N. — Mon, 02 Nov 2009 10:42:10 PST

A force behind both the science and politics of stem cell biology, Weissman now strives to translate his successes to the clinic.

The ubiquitin landscape at DNA double-strand breaks

Messick, T. E., Greenberg, R. A. — Mon, 02 Nov 2009 10:42:10 PST

The intimate relationship between DNA double-strand break (DSB) repair and cancer susceptibility has sparked profound interest in how transactions on DNA and chromatin surrounding DNA damage influence genome integrity. Recent evidence implicates a substantial commitment of the cellular DNA damage response machinery to the synthesis, recognition, and hydrolysis of ubiquitin chains at DNA damage sites. In this review, we propose that, in order to accommodate parallel processes involved in DSB repair and checkpoint signaling, DSB-associated ubiquitin structures must be nonuniform, using different linkages for distinct functional outputs. We highlight recent advances in the study of nondegradative ubiquitin signaling at DSBs, and discuss how recognition of different ubiquitin structures may influence DNA damage responses.

{gamma}-Tubulin ring complexes regulate microtubule plus end dynamics

Mon, 02 Nov 2009 10:42:10 PST

Independently of their nucleation activity, -tubulin ring complex proteins localize along microtubules, limiting catastrophe events during interphase.

From autoinhibition to inhibition in trans: the Raf-1 regulatory domain inhibits Rok-{alpha} kinase activity

Mon, 02 Nov 2009 10:42:10 PST

The mechanism by which Raf-1 antagonizes Rok- to promote migration and tumorigenesis is revealed.

Enhancement of Notch receptor maturation and signaling sensitivity by Cripto-1

Mon, 02 Nov 2009 10:42:10 PST

Cripto-1 associates with Notch1 in the endoplasmic reticulum and Golgi to enhance Notch1 localization to lipid rafts and its maturation.

Ana3 is a conserved protein required for the structural integrity of centrioles and basal bodies

Stevens, N. R., Dobbelaere, J., Wainman, A., Gergely, F., Raff, J. W. — Mon, 02 Nov 2009 10:42:10 PST

Centriolar protein Ana3 is essential for basal body formation, not centriole duplication, as previously thought.

Lateral transport of Smoothened from the plasma membrane to the membrane of the cilium

Milenkovic, L., Scott, M. P., Rohatgi, R. — Mon, 02 Nov 2009 10:42:10 PST

A distinct pathway for ligand-stimulated lateral trafficking of the hedgehog protein Smoothened into cilia is described.

Heterogeneity in the physiological states and pharmacological responses of differentiating 3T3-L1 preadipocytes

Loo, L.-H., Lin, H.-J., Singh, D. K., Lyons, K. M., Altschuler, S. J., Wu, L. F. — Mon, 02 Nov 2009 10:42:11 PST

A systems biology–based analysis shows that differentiating adipocytes look very different at the single-cell level and form distinct cellular subpopulations.

Mammalian Rif1 contributes to replication stress survival and homology-directed repair

Buonomo, S. B.C., Wu, Y., Ferguson, D., de Lange, T. — Mon, 02 Nov 2009 10:42:11 PST

Multifunctional protein Rif1 accumulates at stalled replication forks to facilitate DNA repair during S phase.

Ase1/Prc1-dependent spindle elongation corrects merotely during anaphase in fission yeast

Courtheoux, T., Gay, G., Gachet, Y., Tournier, S. — Mon, 02 Nov 2009 10:42:11 PST

The tug of war that ensues when a kinetochore binds microtubules from both spindle poles is resolved by Ase1/Prc1.

Membrane proteins Bqt3 and -4 anchor telomeres to the nuclear envelope to ensure chromosomal bouquet formation

Mon, 02 Nov 2009 10:42:11 PST

A screen identifies two more bouquet proteins required for meiotic telomere clustering: Bqt4 anchors the telomeres, whereas Bqt3 protects Bqt4 from degradation.

MCL-1-dependent leukemia cells are more sensitive to chemotherapy than BCL-2-dependent counterparts

Brunelle, J. K., Ryan, J., Yecies, D., Opferman, J. T., Letai, A. — Mon, 02 Nov 2009 10:42:11 PST

Cancer-expressed anti-apoptotic protein BCL-2 is stable, whereas MCL-1 undergoes proteasome-dependent degradation in response to chemotherapeutic agents.

Phosphoinositide-dependent kinase 1 controls migration and malignant transformation but not cell growth and proliferation in PTEN-null lymphocytes

Mon, 19 Oct 2009 10:02:31 PDT

Loss of matrix metalloproteinase 2 in platelets reduces arterial thrombosis in vivo

Mon, 19 Oct 2009 10:02:31 PDT

Walking a fine caspase line

Powell, K. — Mon, 19 Oct 2009 10:02:31 PDT

Securing the next generation's peroxisomes

Powell, K. — Mon, 19 Oct 2009 10:02:31 PDT

PIKfyve promotes neuron self-preservation

Powell, K. — Mon, 19 Oct 2009 10:02:31 PDT

The different ties that bind

Short, B. — Mon, 19 Oct 2009 10:02:31 PDT

Two homologues of the cohesin protein Scc3 have specialized roles in chromatid cohesion.

Senthil Muthuswamy: A new road map for cancer

Sedwick, C. — Mon, 19 Oct 2009 10:02:31 PDT

Senthil Muthuswamy uses 3D cell culture to explore the influence of cell polarity on oncogenic transformation.

JCB meeting: Cell Biology of Disease

Misteli, T. — Mon, 19 Oct 2009 10:02:31 PDT

Keratins and protein synthesis: the plot thickens

Kellner, J. C., Coulombe, P. A. — Mon, 19 Oct 2009 10:02:31 PDT

In addition to protecting epithelial cells from mechanical stress, keratins regulate cytoarchitecture, cell growth, proliferation, apoptosis, and organelle transport. In this issue, Vijayaraj et al. (2009. J. Cell Biol. doi:10.1083/jcb.200906094) expand our understanding of how keratin proteins participate in the regulation of protein synthesis through their analysis of mice lacking the entire type II keratin gene cluster.

It takes two to tango to the melanosome

Lakkaraju, A., Carvajal-Gonzalez, J. M., Rodriguez-Boulan, E. — Mon, 19 Oct 2009 10:02:31 PDT

The role of clathrin adaptor proteins in sorting cargo in the biosynthetic and recycling routes is an area of intense research. In this issue, Delevoye et al. (2009. J. Cell Biol. doi:10.1083/jcb.200907122) show that a close interaction between the clathrin adaptor AP-1 and a kinesin motor KIF13A is essential for delivering melanogenic enzymes from recycling endosomes to nascent melanosomes and for organelle biogenesis.

Differential regulation of telomere and centromere cohesion by the Scc3 homologues SA1 and SA2, respectively, in human cells

Canudas, S., Smith, S. — Mon, 19 Oct 2009 10:02:31 PDT

In vertebrates, two Scc3 homologues control sister chromatid cohesion of distinct chromosomal regions.

Keratins regulate protein biosynthesis through localization of GLUT1 and -3 upstream of AMP kinase and Raptor

Vijayaraj, P., Kroger, C., Reuter, U., Windoffer, R., Leube, R. E., Magin, T. M. — Mon, 19 Oct 2009 10:02:31 PDT

Removal of the entire keratin family of intermediate filament proteins from embryonic epithelia has surprising implications for mTOR signaling.

Cohesin SMC1{beta} protects telomeres in meiocytes

Mon, 19 Oct 2009 10:02:31 PDT

Telomeres fail to attach to the nuclear envelope and lose structural integrity in cells lacking SMC1β.

Ubiquilin and p97/VCP bind erasin, forming a complex involved in ERAD

Mon, 19 Oct 2009 10:02:31 PDT

Loss of ubiquilin or erasin activates ER stress, increases accumulation of polyubiquitinated proteins, and shortens lifespan in worms.

Temporal regulation of Drosophila IAP1 determines caspase functions in sensory organ development

Koto, A., Kuranaga, E., Miura, M. — Mon, 19 Oct 2009 10:02:31 PDT

Caspase activation is regulated by the turnover of E3 ubiquitin ligase, DIAP1, and depends on cell type and maturity.

Pex3 peroxisome biogenesis proteins function in peroxisome inheritance as class V myosin receptors

Mon, 19 Oct 2009 10:02:31 PDT

Pex3 links peroxisome formation and inheritance. By binding to class V myosin, biogenesis protein Pex3 also directs the organelles into daughter cells.

AP-1 and KIF13A coordinate endosomal sorting and positioning during melanosome biogenesis

Mon, 19 Oct 2009 10:02:31 PDT

The clathrin adaptor protein AP-1 and the motor KIF13A work together to deliver cargo into maturing melanosomes.

Spred2 interaction with the late endosomal protein NBR1 down-regulates fibroblast growth factor receptor signaling

Mardakheh, F. K., Yekezare, M., Machesky, L. M., Heath, J. K. — Mon, 19 Oct 2009 10:02:31 PDT

Neighbor of BRCA1 (NBR1) suppresses growth factor responses by redirecting activated receptors to lysosomes for degradation.

PIKfyve regulates CaV1.2 degradation and prevents excitotoxic cell death

Tsuruta, F., Green, E. M., Rousset, M., Dolmetsch, R. E. — Mon, 19 Oct 2009 10:02:31 PDT

Neuronal Ca levels are regulated by glutamate receptor activation, which recruits PIKfyve to voltage-gated Ca channels, prompting their degradation.

Postsynaptic regulation of synaptic plasticity by synaptotagmin 4 requires both C2 domains

Barber, C. F., Jorquera, R. A., Melom, J. E., Littleton, J. T. — Mon, 19 Oct 2009 10:02:31 PDT

Analogous to synaptotagmin 1, a calcium-sensitive regulator of presynaptic vesicle fusion, synaptotagmin 4 needs both of its calcium-binding sites to regulate synaptic plasticity via postsynaptic retrograde signaling.

A MUG shot of spindle assembly

Short, B. — Mon, 05 Oct 2009 12:07:44 PDT

Autophagy balances a Highwire act in synapse development

Short, B. — Mon, 05 Oct 2009 12:07:44 PDT

Merkel cells bear the touch of epidermis

Short, B. — Mon, 05 Oct 2009 12:07:44 PDT

Myosins pull together--separately

Leslie, M. — Mon, 05 Oct 2009 12:07:44 PDT

Study suggests that asynchronous molecular motors can integrate their actions.

Irina Conboy: Making the old feel young again

Powell, K. — Mon, 05 Oct 2009 12:07:44 PDT

Conboy has found her niche in chasing down what ails aged, decrepit muscle stem cells.

DNA replication times the cell cycle and contributes to the mid-blastula transition in Drosophila embryos

McCleland, M. L., Shermoen, A. W., O'Farrell, P. H. — Mon, 05 Oct 2009 12:07:44 PDT

Deletion of S phase disrupts mitotic timing in maternally regulated cycles, but it doesn't alter the cell cycle once zygotic transcription has begun.

Tim-Tipin dysfunction creates an indispensible reliance on the ATR-Chk1 pathway for continued DNA synthesis

Smith, K. D., Fu, M. A., Brown, E. J. — Mon, 05 Oct 2009 12:07:44 PDT

Increased amounts of single-stranded DNA accumulate at replication forks when Tim–Tipin isn't around, activating an ATR-mediated DNA damage response necessary for DNA replication to proceed.

INTS3 controls the hSSB1-mediated DNA damage response

Mon, 05 Oct 2009 12:07:44 PDT

MISE is identified as a component of the Integrator complex required for DNA repair.

An eIF4E-binding protein regulates katanin protein levels in C. elegans embryos

Li, W., DeBella, L. R., Guven-Ozkan, T., Lin, R., Rose, L. S. — Mon, 05 Oct 2009 12:07:44 PDT

SPN2 represses katanin translation to prevent mitotic defects (independently of ubiquitin-mediated katanin degradation).

Relative contributions of chromatin and kinetochores to mitotic spindle assembly

O'Connell, C. B., Loncarek, J., Kalab, P., Khodjakov, A. — Mon, 05 Oct 2009 12:07:45 PDT

It's the kinetochores, not the DNA, that initiate spindle assembly.

Coupled myosin VI motors facilitate unidirectional movement on an F-actin network

Sivaramakrishnan, S., Spudich, J. A. — Mon, 05 Oct 2009 12:07:45 PDT

A combination of experimentation and modeling reveal that multiple myosin VI molecules coordinately transport cargo over the actin filament network.

Glyburide inhibits the Cryopyrin/Nalp3 inflammasome

Mon, 05 Oct 2009 12:07:45 PDT

Glyburide, a sulfonylurea drug commonly used to treat type 2 diabetes, shuts down IL-1β secretion by preventing Cyropyrin activation.

Autophagy promotes synapse development in Drosophila

Shen, W., Ganetzky, B. — Mon, 05 Oct 2009 12:07:45 PDT

The ubiquitin–proteosome and autophagy pathways work together to regulate synaptic growth and plasticity in response to environmental conditions.

Intraflagellar transport particle size scales inversely with flagellar length: revisiting the balance-point length control model

Engel, B. D., Ludington, W. B., Marshall, W. F. — Mon, 05 Oct 2009 12:07:45 PDT

Chlamydomonas reinhardtii IFT particle trains, important for flagella maintenance and assembly, are observed to decrease in size as a function of cilia length.

Epidermal progenitors give rise to Merkel cells during embryonic development and adult homeostasis

Mon, 05 Oct 2009 12:07:45 PDT

Lineage-tracing experiments show that the origin of specialized mechanosensory Merkel cells in the skin is epidermal progenitors, not the neural crest.

Molecular mechanisms that enhance synapse stability despite persistent disruption of the spectrin/ankyrin/microtubule cytoskeleton

Massaro, C. M., Pielage, J., Davis, G. W. — Mon, 05 Oct 2009 12:07:45 PDT

Neuromuscular junctions crippled by a disrupted microtubule cytoskeleton are rescued by stress-induced activation of MAPK-JNK-Fos signaling.

Cdc42 antagonizes Rho1 activity at adherens junctions to limit epithelial cell apical tension

Warner, S. J., Longmore, G. D. — Mon, 05 Oct 2009 12:07:45 PDT

Rho promotes actomyosin contractility during epithelial cell remodeling, but Cdc42 keeps the epithelium in shape by limiting RhoA activity.

Electron-tomographic analysis of intraflagellar transport particle trains in situ

Mon, 05 Oct 2009 12:07:45 PDT

Ultrastructural study of Chlamydomonas cilia shows that anterograde IFT particles form trains that are long and narrow, while retrograde IFT form short, compact particle trains.