RHOJ (G3V4H1): evidence and exact-input prediction review

The full-length RHOJ/TCL protein is an active, rapidly exchanging GTPase, contrary to a generic GTPase-deficient Rho-family description. However, G3V4H1 is a substantially altered short product, so its activity cannot be decided from the full-length result in either direction.

Input identity and functional boundary

G3V4H1 and Q9H4E5 share HGNC:688. The first 103 residues match exactly; the remainder is highly divergent. The reference guanine-binding residue 136 is not aligned to the target, reference binding residue 177 is not conserved, and the terminal lipidation region is absent from the conserved segment. Retaining the P-loop and switch-region segment alone does not establish a functional G-domain.

Biological evidence

In vitro, TCL shows rapid GDP/GTP
exchange and displays higher GTP dissociation and hydolysis rates than TC10.

Chimeras of TCL and TC10
revealed amino acids 121-129 of TCL contributed to the differences in nucleotide
loading.

Exact non-GO claims

The complete emitted record is preserved in RHOJ-protnlm-source.json. Assessments below address the selected protein product; evidence on longer products is identified explicitly.

Protein name

Cell division control protein 42 homolog

LSP (CS 2) if “homolog” is read as a broad relationship: RHOJ is demonstrably Cdc42-related. The name is less informative than RHOJ/TCL and must not be read as identifying the CDC42 paralog or guaranteeing an intact Cdc42-like enzyme. PMID:10967094(https://pubmed.ncbi.nlm.nih.gov/10967094/).

Function

Binds GTP but lacks intrinsic GTPase activity and is resistant to Rho-specific GTPase-activating proteins

UNC (CS 1) for the selected G3V4H1 product. The “lacks intrinsic GTPase activity” description is contradicted for full-length RHOJ by direct hydrolysis measurements, but the target has a divergent, incomplete G-domain. The conjunction “binds GTP but lacks hydrolysis and resists GAPs” requires binding, hydrolysis and GAP assays of this exact product; a truncation alone does not establish an atypical GTPase mechanism. PMID:10967094(https://pubmed.ncbi.nlm.nih.gov/10967094/); sequence mapping.

Location

Membrane

UNC (CS 1). The selected product does not retain the reference C-terminal membrane-targeting region, and RHOJ membrane association is sensitive to sequence-dependent nucleotide loading. Partner-mediated membrane association remains possible, so no exclusively cytosolic alternative is asserted. PMID:27660391(https://pubmed.ncbi.nlm.nih.gov/27660391/).

No GO or EC term was emitted in this record; the name, function and location assessments above constitute its prediction review.

Family integration

PTHR24072 establishes Rho-family ancestry but includes paralogs with different nucleotide cycling properties. The experimentally characterized RHOJ branch is catalytically active. The selected altered product creates an additional product-integrity boundary beyond family membership.

Evidence limits

The original RHOJ paper is abstract-only in the cache; the 2016 mechanistic study has full text. Neither tests G3V4H1. A confident pseudoenzyme designation would conflate a potentially incomplete product with a stable, evolved GTPase-deficient signaling protein.

Exact sequence mapping: RHOJ-bioinformatics/RESULTS.md. Global alignments can place nonhomologous alternative tails opposite gaps or distant residues; only conserved segments and explicitly retained feature intervals support functional transfer.

Research integration

The genuine Falcon report is retained. Its gene-level synthesis is interpreted through the exact product sequence and the primary sources above; the truncation boundary and paralog distinctions are assessed independently.