Cloning and functional characterization of the HRASLS2 gene

Abstract

The HRAS-like suppressor 2 (HRASLS2) gene belongs to the H-REV107 gene family involved in the regulation of cell growth and differentiation. HRASLS2 is expressed at high levels in normal tissues of the small intestine, kidney, and trachea. We cloned HRASLS2 cDNA from human SW480 colon cancer cells. Most wild-type, and some N- and C-terminal truncated HRASLS2 (HRASLS2DeltaNDeltaC) were expressed as a granular pattern located at perinuclear region in HtTA cervical cancer cells, while truncation at the C-terminus only (HRASLS2DeltaC) resulted in a diffuse pattern. Wild-type HRASLS2 significantly suppressed colony formation of HeLa and HCT116 cells. HRASLS2DeltaNDeltaC significantly inhibited colony formation of HCT116 cells, but HRASLS2DeltaC did not affect cell growth. HRASLS2 suppressed the RAS-GTP levels and total RAS protein by 44% and 25%, respectively in HtTA cells; however, the suppression was not observed in truncated HRASLS2 variants. In conclusion, the HRASLS2 protein suppressed growth and RAS activities of cancer cells, and the C-terminal hydrophobic domain appeared to be indispensable for both activities.

Enzymological analysis of the tumor suppressor A-C1 reveals a novel group of phospholipid-metabolizing enzymes

“…Contribution of the catalytic activities to their tumor-suppressive activities currently remains unclear. The tumor-suppressing activity was mostly implicated in Ras-transformed cells ( 11,13,16,33 ), and the mutants of TIG3 addressed to the conserved asparagine and cysteine residues failed to induce the apoptosis of HtTA cervical cancer cells, which was caused by the wild-type ( 34 ). Because this cysteine residue functions as the catalytic center, it is possible that the phospholipid-metabolizing activity of the tumor suppressors regulates the function of Ras by altering the membrane structures of microdomains where Ras is specifi cally localized ( 35 ).…”

Phospholipase A/Acyltransferase enzyme activity of H-rev107 inhibits the H-RAS signaling pathway

“…H-rev107 is a member of the HREV107 type II tumor suppressor gene family, which includes H-REV107, retinoid-inducible gene 1 (RIG1) [5], HRASLS2 [6,7], HRLP5 [8], and HRASLS (A-C1) [9,10], the last of which is present in humans, rats, and mice. In this family, the protein contains an NC domain at the N-terminus and a hydrophobic membrane-anchoring domain at the C-terminus [11,12].…”

Regulation of Peroxisomal Lipid Metabolism by Catalytic Activity of Tumor Suppressor H-rev107

“…[1][2][3][4][5][6][7][8][9][10][11][12][13][14] C]Hexadecanol was from Moravek Biochemicals (Brea, CA). Horseradish peroxidase-linked anti-mouse IgG, horseradish peroxidase-linked anti-rabbit IgG, Hybond P, and an ECL Plus kit were from GE Healthcare.…”

“…In human beings, the HRAS-like suppressor (HRASLS) 2 family, or H-rev107 family, consists of five protein molecules (H-rev107, TIG3 (tazarotene-induced gene 3), A-C1, HRASLS2, and Ca 2ϩ -independent N-acyltransferase) sharing a common structure (1,2). H-rev107 is the first member of this family to be discovered and has been characterized as a type II tumor suppressor (3)(4)(5).…”