Tctex1 Domain Containing Protein 4 (TCTEX1D4)

TCTEX1D4 encodes a predicted 221-amino acid protein that is a member of the Tctex1/2 family of cytoplasmic dynein light chains. TCTEX1D4 has a predicted molecular mass of 23 kD and contains several phosphorylation sites. RT-PCR analysis demonstrated expression of TCTEX1D4 in many tissues, including vascular endothelial and smooth muscle cells, placenta, and testis. High expression was seen in human umbilical vein endothelial cells and a large-cell lung cancer cell line. EGFP-tagged TCTEX1D4 demonstrated localization throughout the cytoplasm and nucleus.TCTEX1D4 colocalized with endoglin and TGFBR2 in a multimeric complex at the cell membrane. Overexpression of TCTEX1D4 resulted in increased amounts of endoglin and TGFBR2 and had a strong inhibitory effect on TGFB signaling.