StAR-related lipid transfer domain protein 13 (STARD13) also known as deleted in liver cancer 2 protein (DLC-2) is a

protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, res ...

that in humans is encoded by the ''STARD13''

gene In biology, the word gene (from , ; "... Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a b ...

and a member of the DLC family of proteins.

Function and structure

STARD13 serves as a Rho GTPase-activating protein (GAP), a type of protein that regulates members of the

Rho family of GTPases The Rho family of GTPases is a family of small (~21 kDa) signaling G proteins, and is a subfamily of the Ras superfamily. The members of the Rho GTPase family have been shown to regulate many aspects of intracellular actin dynamics, and are foun ...

. It selectively activates

RhoA Transforming protein RhoA, also known as Ras homolog family member A (RhoA), is a small GTPase protein in the Rho family of GTPases that in humans is encoded by the ''RHOA'' gene. While the effects of RhoA activity are not all well known, it is ...

and CDC42 and suppresses cell growth by inhibiting

actin Actin is a family of globular multi-functional proteins that form microfilaments in the cytoskeleton, and the thin filaments in muscle fibrils. It is found in essentially all eukaryotic cells, where it may be present at a concentration of ov ...

stress fiber assembly. The protein consists of an N-terminal sterile alpha motif (SAM) domain, a serine-rich domain, a

RhoGAP domain RhoGAP domain is an evolutionary conserved protein domain of GTPase activating proteins towards Rho/ Rac/ Cdc42-like small GTPases. Human proteins containing this domain ABR; ARHGAP1; ARHGAP10; ARHGAP11A; ARHGAP11B; ARHGAP12; AR ...

and at the C-terminus, a StAR-related lipid-transfer domain ( START).

Tissue distribution and pathology

The protein was identified in part through its differential expression in

cancers Cancer is a group of diseases involving abnormal cell growth with the potential to invade or spread to other parts of the body. These contrast with benign tumors, which do not spread. Possible signs and symptoms include a lump, abnormal bl ...

. A low level of STARD13 was observed in less differentiated hepatocellular carcinoma tissue with higher RhoA expression. A small patient study finds that the absence of STARD13 in hepatocellular carcinomas correlates with higher levels of RhoA and a poorer prognosis than patients with carcinomas that were STARD13-positive.

Function and structure

Tissue distribution and pathology

References

Further reading