Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain
the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in
Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles
and JavaScript.
Case and Waterman discuss how integrating extracellular-matrix-bound integrins and the actin cytoskeleton into a mechanosensitive molecular clutch transmits actin-cytoskeleton-generated forces to the extracellular matrix through focal adhesions.
Control of stem cell activity is essential for accurate regeneration. Pathogen- or chemical-induced intestinal damage is now shown to recruit haemocytes expressing bone morphogenetic protein signals that stimulate proliferation of intestinal stem cells and subsequently induce their quiescence, in conjunction with muscle-derived bone morphogenetic proteins. A temporal switch in expression of Type I receptors enables this two-phase response.
Cancer cells are known to secrete exosomes with pro-metastatic effects. Pancreatic-cancer-derived exosomes are now shown to promote liver metastasis by eliciting pre-metastatic niche formation through a multi-step process. This involves uptake of exosome-derived factors by liver Kupffer cells and hepatic stellate cell activation to generate a fibrotic microenvironment with immune cell infiltrates that favours metastasis.
A major controversy in the field of chromosome research has been whether condensin is required for achieving the highly compacted state of chromatin fibres in mitosis and meiosis. Through genetic experiments in mouse oocytes, condensin is now found to be indispensable for meiotic chromosome assembly by mediating chromosome compaction and disentanglement of sister chromatids and by conferring rigidity to chromosomes.
Whether the cancer cells responsible for the growth of primary tumours are also able to re-initiate tumour growth after seeding to distant organs is unclear. The characterization of breast cancer cells with both of these attributes now identifies the functional and molecular determinants necessary to mediate primary tumour formation and re-initiation at the secondary site.
How proteins migrate through the interconnected organelles of the endolysosomal system is poorly understood. A piece of the puzzle has been added with the identification of a complex of tethering factors that functions in the recycling of proteins towards the cell surface.
Yap and Lecuit review the interplay of E-cadherin-mediated adhesion and actomyosin-based contractility, and discuss the functional effects of their crosstalk at the cellular and tissue level.
Excess caloric intake leads to both the growth of existing fat cells and the generation of new adipocytes. New findings show that PI3K–Akt2 signalling is involved in the differentiation of adult adipose precursor cells — a pathway not required for adipogenesis in the embryo.
The kinase AMPK, a sensor of cellular energy stress, has been shown to oppose the growth-promoting activity of YAP, the transcriptional co-activator downstream of the Hippo signalling pathway. This finding may help to explain why the antidiabetic drug metformin, for which AMPK is a key effector, is linked to cancer-protective activity.
Burroughs and DeBerardinis discuss the metabolic pathways that tumour cells employ to promote their survival and proliferation, and present the current approaches to study cancer metabolism in an in vivo setting.
Cells often migrate in tightly connected groups with coordinated movement and polarity. The collective migration of epithelial cell sheets is now shown to be mediated by a signalling axis that involves the merlin tumour-suppressor protein, the tight-junction-associated angiomotin–Rich1 complex and the Rac1 small GTPase.
Selective autophagy is essential for maintaining cellular homeostasis under different growth conditions. Huntingtin, mutated versions of which have been implicated in Huntington disease, is now shown to act as a scaffold protein that couples the induction of autophagy and the selective recruitment of cargo into autophagosomes.
Berninger and colleagues define milestones for in vivo reprogramming and discuss recent developments in reprogramming into pancreatic b-cells and neurons.
The protrusion of cilia into extracellular space provides cells with sensors of localized environmental cues that include fluid flow, mechanical force and important growth factors such as Hedgehog. Live imaging has now captured the initial appearance of cilia during embryogenesis, and defined lineage-specific determinants that restrict extra-embryonal ciliogenesis.
Macrophages facilitate tumour progression, but it is unclear whether this capability is influenced by tumour-initiating cells. Glioblastoma stem cells are now shown to secrete periostin, a matrix protein that recruits protumoral macrophages and enhances glioblastoma progression in mice.
