Transmembrane protein 44 (TMEM44)

Transmembrane protein 44 (TMEM44) is a multi-pass transmembrane protein in humans encoded by the TMEM44 gene, located on chromosome 3q29[1][3]. The protein has a predicted molecular weight of 47.1 kDa and is composed of 428 amino acids with seven transmembrane domains[1][3]. TMEM44 is integrated within the endoplasmic reticulum membrane, with its C-terminus orientated in the cytoplasm. Multiple splice isoforms are known, and the gene shows low-level expression across various tissues such as brain, bone, ovary, pancreas, uterus, and eye[1][3][6]. Expression has been detected in tumors including those from gastrointestinal tract, ovary, pancreas, muscle, uterus, and brain[1][6]. While the exact function is unknown, TMEM44 is predicted to have basic amino acid transporter activity and belongs to the Lysosomal/Vacuolar Amino Acid Transporter family[5][7], but this function has not been definitively confirmed. Experimentally, TMEM44 has predicted interactions with proteins like GSK3B, KAT6B, and SPAG9, but a direct signaling or disease mechanism is not established[1][3]. Currently, there are no approved drugs or selective chemical modulators for TMEM44, and it is not recognized as a direct therapeutic target in established drug discovery or clinical practice. TMEM44 is not a well-characterized therapeutic target and its direct molecular functions remain largely unknown. Some literature and databases note its predicted transporter activity; other studies have focused on related non-coding RNAs from the TMEM44 locus, but not the protein itself. TMEM44-AS1, a long non-coding RNA, is associated with cancer progression and is a potential biomarker, but this is distinct from the TMEM44 protein[2][4]. In summary, TMEM44 (Transmembrane protein 44) is a putative membrane transporter protein with unknown confirmed biological function, expressed at low levels in a range of tissues, and occasionally upregulated in tumors. It is not currently considered a validated therapeutic target due to insufficient evidence regarding its physiological or pathological roles[1][3][5][7].

Other names

TMEM44DKFZp686O18124transmembrane protein 44