GO_REF:0000044

Gene Ontology annotation based on UniProtKB/Swiss-Prot Subcellular Location vocabulary mapping, accompanied by conservative changes to GO terms applied by UniProt

UniProt SUBCELLULAR LOCATION for RvLEAM (A0A0E4AVP3) records mitochondrial localization with experimental backing from PMID:25675104 (immunohistochemistry in tardigrade cells; RvLEAM-GFP co-localizes with MitoTracker Red in human cells) and a predicted N-terminal mitochondrial transit peptide (aa 1-31). This mapping reference is used to convert the controlled-vocabulary mitochondrial location into the GO:0005739 (mitochondrion) annotation with IEA evidence.

PMID:25675104

Novel mitochondria-targeted heat-soluble proteins identified in the anhydrobiotic Tardigrade improve osmotic tolerance of human cells

RvLEAM is the first mitochondrial LEA protein identified in tardigrades

"we identified two novel mitochondrial heat-soluble proteins, RvLEAM and MAHS (Mitochondrial Abundant Heat Soluble), as potent mitochondrial protectants from Ramazzottius varieornatus"
Immunohistochemistry confirmed mitochondrial localization in tardigrade cells

"RvLEAM is a group3 LEA protein and immunohistochemistry confirmed its mitochondrial localization in tardigrade cells"
Expression of RvLEAM improved hyperosmotic tolerance of human cells

"we demonstrated that RvLEAM protein as well as MAHS protein improved the hyperosmotic tolerance of human cells"
RvLEAM and MAHS have protective roles in water-deficient environments

"tardigrade mitochondria contain at least two types of heat-soluble proteins that might have protective roles in water-deficient environments"
LEA proteins are involved in desiccation tolerance

"Late Embryogenesis Abundant (LEA) proteins are heat-soluble proteins involved in the desiccation tolerance of many anhydrobiotic organisms"

PMID:27649274

Extremotolerant tardigrade genome and improved radiotolerance of human cultured cells by tardigrade-unique protein

Genome sequencing of R. varieornatus (YOKOZUNA-1 strain)

file:RAMVA/RvLEAM/RvLEAM-deep-research-falcon.md

Deep research synthesis on RvLEAM (A0A0E4AVP3) from R. varieornatus

RvLEAM shows sequence similarity to nematode LEA proteins (e-value < 1e-05) and matches the LEA-related PANTHER motif PTHR23241, with nine LEA-like 11-mer motifs consistent with group 3 LEA architecture and predicted amphipathic helical repeats.
RvLEAM is highly hydrophilic (GRAVY -0.94) with no transmembrane region, consistent with a soluble protein; combined with the N-terminal mitochondrial transit peptide this strongly implies mitochondrial matrix rather than membrane localization.
Heterologous expression in human HEp-2 cells significantly improves hyperosmotic tolerance (~2x metabolic activity at 300 mM sucrose for 48 h), supporting a transferable cell-autonomous protective function consistent with the LEA family molecular-shield model.