målSNAREs

MålSNAREs are a proposed class of SNARE proteins posited to function as target-membrane SNAREs that determine the specificity of vesicle fusion events. The term has appeared in a limited set of studies on eukaryotic membrane trafficking and is not part of the broadly accepted SNARE taxonomy.

Structure. Like canonical SNAREs, målSNAREs are predicted to contain a coiled-coil SNARE motif that forms a four-helix bundle with cognate v-SNAREs during fusion, and to be anchored in membranes by a C-terminal transmembrane domain. Some reports describe additional regulatory domains that may influence localization or interaction with tethering factors.

Localization and function. They are proposed to reside on target membranes (for example, Golgi or plasma membrane) and to participate in the formation of trans-SNARE complexes that drive membrane fusion. Specific partnerships with vesicle-associated SNAREs are thought to confer targeting specificity and regulate fusion efficiency, potentially in concert with Rab GTPases and tethering complexes.

Evidence and status. The concept of målSNAREs remains somewhat controversial, with most evidence based on computational predictions, limited biochemical interactions, and occasional genetic phenotypes. No universally accepted consensus has emerged regarding their exact number, partners, or roles across species.

See also. SNARE, vesicle fusion, membrane trafficking.