pinnavalkude

Pinnavalkude is a term used in Estonian to denote proteins located on the cell surface, i.e., proteins associated with the plasma membrane that extend into the extracellular space. They play a key role in how cells interact with their environment and other cells. The subcategory includes integral membrane proteins with transmembrane domains, as well as GPI-anchored and lipid-associated proteins, and peripheral membrane proteins that associate with the membrane.

Localization is achieved via signal peptides and cellular trafficking through the secretory pathway. Most surface proteins participate in one or more of these functions: transmitting signals through receptors; transporting ions or molecules via channels and transporters; mediating cell adhesion to other cells or to the extracellular matrix; catalyzing extracellular reactions; and enabling immune recognition through antigen presentation.

Examples include receptor proteins such as receptor tyrosine kinases, ion channels, and adhesion molecules like integrins and selectins, as well as MHC molecules involved in immune presentation. Many pinnavalkude are glycosylated, with carbohydrate chains that influence stability and interactions.

Clinical relevance: Aberrant expression, mutation, or aberrant glycosylation of pinnavalkude is associated with diseases including cancer, autoimmune disorders, and infectious diseases. They are common drug targets (antibody therapies, vaccines) and serve as diagnostic or prognostic biomarkers.

Research and methods: Techniques to study surface proteins include flow cytometry with specific antibodies, immunohistochemistry, surface biotinylation, proteomics, and imaging approaches.

Etymology: The word pinnavalkude is used in Estonian to denote surface proteins; it is commonly analyzed as a combination of pinna (“surface”) and valk (“protein”), with the plural suffix -ude. This is a general overview of surface proteins across cell types and organisms.