The scribble-Dlg-Lgl module in cell polarity regulation

Although the Scribble polarity module has long been known as a key regulator of apicobasal polarity, it is only recently that its broader role in the control of near all polarity states and transitions is being appreciated. Here we review the Scribble module in the regulation of cell polarity and other cellular functions at the molecular and cellular level. The more recent detailed analysis of multiple vertebrate models for each of its component homologues, Scribble, Dlg and Lgl, has revealed specific but also common roles for individual homologues in a variety of developmental contexts. In addition, emerging data has also implicated the Scribble polarity module in human developmental syndromes and the etiology of human cancer, highlighting a need for a better understanding of this polarity module for therapeutic purposes. Unlocking the temporal and spatial coordination of the myriad interactions that these signaling scaffolds regulate is a major challenge for the field and will be key to resolve the function of Scribble, Dlg, and Lgl in the control of cell polarity and tissue architecture

Biochemical Interaction Between Muscle and Bone: A Physiological Reality?

In elderly with a sedentary lifestyle, often suffering from sarcopenia to osteopenia, a training intervention could be an effective countermeasure for bone as well as muscle. Both bone and muscle adapt their mass and strength in response to mechanical loading in part via similar signaling pathways. Bone as well as muscle produces a wide variety of growth factors and cytokines in response to mechanical loading, which are important for their adaptations. It has been hypothesized that in addition to mechanical stimuli, muscle and bone communicate by these factors. Whether such biochemical interaction between both tissues is physiological is a still subject of debate. Here, we provide an overview of a range of biological factors possibly involved in the biochemical cross talk between bone and muscle. In addition, we discuss the plausibility that such interactions are involved in non-pathological adaptation of both tissues, either in paracrine or in endocrine fashion. As yet, convincing experimental evidence for biochemical cross talk between muscle and bone is very limited. Several studies have shown that muscle-derived factors are involved in bone fracture healing as well as in bone adaptation in case of muscle pathology. For involvement of cross talk between muscle and bone in physiological adaptation, there is no definite proof yet. Detailed knowledge of the biochemical interactions between muscle and bone is of clinical importance. It can help to discover pharmacological treatment to be used alone or in parallel with exercise training, thereby reducing the need for high-impact exercise. © 2014 Springer Science+Business Media New York