dineínas

Dineínas are a family of motor proteins that move along microtubules toward the minus end, using energy from ATP hydrolysis. They are essential for a range of cellular processes, including intracellular transport, organelle positioning, and the beating of cilia and flagella. In eukaryotic cells, dineínas are divided into two broad groups: cytoplasmic dineínas, which carry diverse cargoes toward the cell center, and axonemal dineínas, which drive the sliding of microtubules within cilia and flagella to produce movement.

Cytoplasmic dineínas include cytoplasmic dynein-1 and dynein-2, each forming large multi-subunit complexes with a heavy chain that contains the ATPase motor domain, along with intermediate and light chains that mediate cargo binding and regulation. The activity and targeting of cytoplasmic dineínas are aided by adaptor complexes such as dynactin, as well as regulatory factors like LIS1. Axonemal dineínas, by contrast, are arranged as outer and inner dynein arms in the axoneme of cilia and flagella and generate the bending motions required for motility.

Mechanistically, the heavy chain’s AAA+ ATPase ring undergoes conformational changes upon ATP binding and hydrolysis, translating chemical energy into mechanical work that moves along microtubules. The dynein complex often requires accessory proteins to achieve processive, long-range movement, and its activity is tightly coordinated with microtubule dynamics and other motor systems.

Dysfunctions in dineín subunits or regulators are associated with human diseases, including primary ciliary dyskinesia, certain neurodevelopmental and neurodegenerative disorders, and various ciliopathies. Research into dineínas continues to illuminate their roles in cellular logistics, development, and disease.