Basolateraalin

Basolateraalin is a term used in cell biology to describe the basolateral domain of epithelial and endothelial cells. It denotes the surface region that faces the basal lamina and the surrounding tissue, as opposed to the apical domain, which faces the lumen or external environment. In polarized epithelia, the basolateral and apical membranes are separated by tight junctions, which maintain distinct compositions and functions for each domain.

The basolateral region includes the basolateral membrane and the lateral membranes that contact neighboring cells. This domain is anchored to the extracellular matrix via the basal lamina and integrins, contributing to cell adhesion and tissue architecture. It also hosts specific transporters, receptors, and enzymes essential for inward and outward transport of ions, nutrients, and signaling molecules. Notable components often enriched in the basolateral membrane include the Na+/K+-ATPase and various solute carriers that drive vectorial transport across epithelia.

Protein sorting and trafficking mechanisms govern whether a given membrane protein is delivered to the basolateral or apical surface. Basolateral sorting signals, such as tyrosine-based motifs and dileucine motifs, direct cargo via clathrin-coated pathways and adaptor molecules (for example, AP-1B in vertebrates). Proper basolateral targeting is crucial for maintaining cell polarity and coordinated tissue function.

Dysfunction of basolateral polarity or sorting can contribute to disease, including certain cancers and kidney disorders, where loss of epithelial organization disrupts barrier function and transport. Basolateraalin remains a key concept in histology and physiology for understanding epithelial biology.