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In biology, juxtacrine signalling (or contact-dependent signalling) is a type of cell / cell or cell / extracellular matrix signalling in multicellular organisms that requires close contact. Hence, this stands in contrast to releasing a signaling molecule by diffusion into extracellular space, or the use of long-range conduits like membrane nanotubes and cytonemes (akin to 'bridges'), or the use of extracellular vesicles like exosomes or microvesicles (akin to 'boats'). There are three types of juxtacrine signaling: # A membrane ligand (protein, oligosaccharide, lipid) and a membrane protein of two adjacent cells interact. # A communicating junction links the intracellular compartments of two adjacent cells, allowing transit of relatively small molecules. # An extracellular matrix glycoprotein and a membrane protein interact. Additionally, in unicellular organisms such as bacteria, juxtacrine signaling refers to interactions by membrane contact. The term "juxtacrine" was originally introduced by Anklesaria ''et al.'' (1990) to describe a possible way of signal transduction between TGF alpha and EGFR. Juxtacrine signaling has been observed for some growth factors, cytokine and chemokine cellular signals, playing an important role in the immune response. It has a critical role in development, particularly of cardiac and neural function. Other types of cell signaling include paracrine signalling and autocrine signalling. ==Cell / cell signaling== In this type of signaling, a cell places a specific ligand on the surface of its membrane, and subsequently another cell can bind it with an appropriate cell surface receptor or cell adhesion molecule. An important example is the Notch signalling, notably involved in neural development. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Juxtacrine signalling」の詳細全文を読む スポンサード リンク
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