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1. Biochemical principles of SMAD signaling across the animal kingdom

   https://doi.org/10.1042/BCJ20250135  

   Shaikh, Razeen; Frank, Caitlin; Larson, Nissa J; Chen, Hung-Yuan; Pradhan, Anuj Girish; Mendiola, Kailee; Hanjaya-Putra, Donny; Umulis, David M; Zartman, Jeremiah; Reeves, Gregory T; et al (July 2026, Biochemical Journal)

   Abstract The bone-morphogenetic protein (BMP)-SMAD signal transduction pathway regulates fundamental cellular processes such as fate specification, tissue patterning, and stem cell homeostasis across metazoans and has a conserved signaling architecture. However, the quantitative dynamics of SMAD signaling and regulatory strategies governing pathway activity show a wide range of variation across developmental and stem-cell systems. In the present review, we summarize insights from six major biological contexts—Drosophila embryo, germline stem cells, and the larval and pupal wing discs; the Danio rerio (zebrafish) embryo; and human pluripotent stem cells—to compare how BMP signals are measured, manipulated, modeled, and integrated. We begin by outlining the canonical BMP signaling pathway and the mechanisms of BMP gradient formation across developmental systems, highlighting how conserved pathway components contribute to the formation of system-specific spatial profiles. We then summarize intracellular Smad dynamics and how endogenous pathway dynamics are measured through quantitative imaging of the phosphorylated Smad. Next, we examine how BMP signaling is interpreted through tiered transcriptional responses of downstream target genes. Next, we summarize the mechanistic and computational models of integrated gradient formation, signal transduction, and gene regulation across the presented systems. These insights reveal unifying design principles and performance objectives that govern BMP-SMAD signaling across species and cell types and frame open questions for future cross-species and translational studies. 

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2. Protein kinase sensors: an overview of new designs for visualizing kinase dynamics in single plant cells

   https://doi.org/10.1093/plphys/kiab277  

   Zhang, Li; Takahashi, Yohei; Schroeder, Julian I. (June 2021, Plant Physiology)

   Abstract Protein kinase dynamics play key roles in regulation of cell differentiation, growth, development and in diverse cell signaling networks. Protein kinase sensors enable visualization of protein kinase activity in living cells and tissues in time and space. These sensors have therefore become important and powerful molecular tools for investigation of diverse kinase activities and can resolve long-standing and challenging biological questions. In the present Update, we review new advanced approaches for genetically encoded protein kinase biosensor designs developed in animal systems together with the basis of each biosensor’s working principle and components. In addition, we review recent first examples of real time plant protein kinase activity biosensor development and application. We discuss how these sensors have helped to resolve how stomatal signal transduction in response to elevated CO2 merges with abscisic acid signaling downstream of a resolved basal SnRK2 kinase activity in guard cells. Furthermore, recent advances, combined with the new strategies described in this Update, can help deepen the understanding of how signaling networks regulate unique functions and responses in distinct plant cell types and tissues and how different stimuli and signaling pathways can interact. 

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3. Pseudophosphatases as Regulators of MAPK Signaling

   https://doi.org/10.3390/ijms222212595  

   Hepworth, Emma Marie; Hinton, Shantá D. (November 2021, International Journal of Molecular Sciences)

   Mitogen-activated protein kinase (MAPK) signaling pathways are highly conserved regulators of eukaryotic cell function. These enzymes regulate many biological processes, including the cell cycle, apoptosis, differentiation, protein biosynthesis, and oncogenesis; therefore, tight control of the activity of MAPK is critical. Kinases and phosphatases are well established as MAPK activators and inhibitors, respectively. Kinases phosphorylate MAPKs, initiating and controlling the amplitude of the activation. In contrast, MAPK phosphatases (MKPs) dephosphorylate MAPKs, downregulating and controlling the duration of the signal. In addition, within the past decade, pseudoenzymes of these two families, pseudokinases and pseudophosphatases, have emerged as bona fide signaling regulators. This review discusses the role of pseudophosphatases in MAPK signaling, highlighting the function of phosphoserine/threonine/tyrosine-interacting protein (STYX) and TAK1-binding protein (TAB 1) in regulating MAPKs. Finally, a new paradigm is considered for this well-studied cellular pathway, and signal transduction pathways in general. 

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4. The Rheology of Living Tissues: From Cells to Organismal Mechanics

   https://doi.org/10.1146/annurev-conmatphys-071125-054711  

   Kayal, Sayantani; Nguyen, Anh Q; Bi, Dapeng (March 2026, Annual Review of Condensed Matter Physics)

   Biological tissue rheology investigates the mechanical behavior of tissues, emphasizing their viscoelastic and plastic properties that enable both solid-like elasticity and fluid-like viscosity under mechanical stress. These mechanical characteristics are pivotal in various physiological processes, such as embryonic development, tissue remodeling, wound healing, and pathological conditions including cancer metastasis. The mechanical responses of tissues, shaped by cellular forces and extracellular matrix dynamics, are crucial for maintaining tissue integrity and functionality. Rheological behaviors such as viscoelasticity, plasticity, and active mechanical responses underlie critical biological functions, enabling tissues to adapt structurally and functionally to internal and external stimuli. Recent theoretical and experimental advances have illuminated the complex interplay among cellular mechanics, biochemical signaling, and tissue-level forces, highlighting their roles in governing tissue morphogenesis, repair, and disease progression. This review synthesizes current knowledge, identifies key challenges, and discusses future directions for research in biological tissue rheology. 

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5. Morphogen Patterning in Dynamic Tissues

   https://doi.org/10.1103/h74q-3dgj  

   Plum, Alex M; Serra, Mattia (November 2025, PRX Life)

   Embryogenesis integrates morphogenesis—coordinated cell movements—with morphogen patterning and cell differentiation. While largely studied independently, morphogenesis and patterning often unfold simultaneously in early embryos. Yet how cell movements affect morphogen transport and cells' exposure over time remains unclear, as most pattern formation models assume static tissues. Here we develop a theoretical framework for morphogen patterning in dynamic tissues, recasting advection-reaction-diffusion equations in the cells' moving reference frames. This framework (i) elucidates how morphogenesis mediates morphogen transport and compartmentalization: cell-cell diffusive transport is enhanced at multicellular flow attractors, while repellers act as barriers, affecting cell fate induction and bifurcations. (ii) It formalizes cell-cell signaling ranges in dynamic tissues, deconfounding morphogenetic movements to identify which cells could communicate via morphogens. (iii) It provides two new nondimensional numbers to assess when and where morphogenesis affects morphogen transport. We demonstrate this framework by analyzing classical patterning models with common morphogenetic motifs as well as experimental tissue flows. Our work rationalizes dynamic tissue patterning in development, constraining candidate patterning mechanisms and parameters using accessible cell motion data. 

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