LARP4

Last update 08 May 2025

Basic Info

Synonyms

La ribonucleoprotein 4, La ribonucleoprotein domain family member 4, La-related protein 4

+ [2]

Introduction

RNA binding protein that binds to the poly-A tract of mRNA molecules (PubMed:21098120). Associates with the 40S ribosomal subunit and with polysomes (PubMed:21098120). Plays a role in the regulation of mRNA translation (PubMed:21098120). Plays a role in the regulation of cell morphology and cytoskeletal organization (PubMed:21834987, PubMed:27615744).

100 Clinical Results associated with LARP4

100 Translational Medicine associated with LARP4

0 Patents (Medical) associated with LARP4

Literatures (Medical) associated with LARP4

01 Mar 2025·Laboratory Investigation

NKX3.1 Helps Distinguish Hyalinizing Clear Cell Carcinoma From Other Clear Cell Salivary Gland Neoplasms

Article

Author: Fushimi, Chihiro ; Nishino, Shogo ; Sakyo, Airi ; Yatabe, Yasushi ; Mori, Akiko ; Honma, Yoshitaka ; Takahashi, Hideaki ; Sakai, Toshihiko ; Kobayashi, Kenya ; Kato, Hiroko ; Yoshimoto, Seiichi ; Yokoyama, Kazuki ; Mori, Taisuke ; Sakai, Azusa ; Ryo, Eijitsu ; Hatano, Toshiyuki ; Matsumoto, Fumihiko ; Eguchi, Kohtaro ; Yoshida, Akihiko ; Omura, Go

Hyalinized clear cell carcinoma (HCCC) is a rare tumor of the minor salivary gland, characterized by pale cytoplasm and EWSR1::ATF1 fusion. Recently, new fusions, such as EWSR1::LARP4 and SMARCA2::CREM, have also been identified. Histologically, HCCC closely resembles other salivary gland tumors like mucoepidermoid carcinoma and myoepithelial carcinoma, and there are no specific immunohistological markers for its identification. In this study, we investigated potential markers for HCCC based on the characteristics of minor salivary gland acini, from which these tumors may originate. SOX10 is a known marker for serous gland clusters and NKX3.1 for mucus gland clusters. Fluorescence intensity analysis of double staining, objectively evaluated by artificial intelligence, revealed variations in the positive intensity of cells single positive for NKX3.1 and SOX10, as well as cells positive for both markers, which are commonly observed in normal minor salivary glands. We evaluated NKX3.1 expression by immunohistochemistry in 12 HCCC cases (including 9 EWSR1::ATF1, 1 EWSR1::LARP4, and 1 SMARCA2::CREM), 12 myoepithelial carcinoma cases, and tissue microarray containing 88 cases of multiple salivary gland tumors using immunohistochemistry. NKX3.1 was expressed in all 12 HCCC cases (100%), with NKX3.1-positive cells ≧90% in 3 cases, ≧60% 1 case, ≧30% 4 cases, and <30% 4 cases, respectively. SOX10 was negative in 10 cases and weakly positive in 2 cases. This finding mimics the pattern of expression in minor salivary glands and may explain the occurrence of weak NKX3.1 staining and SOX10-positive cases in HCCC. Additionally, in the tissue microarray analysis, NKX3.1 staining was observed in only 1 HCCC case. These findings indicate that NKX3.1 is a useful marker for distinguishing HCCC from other clear cell salivary gland neoplasms. This study suggests that NKX3.1, along with SOX10 and CK7, can be utilized to improve the accuracy of HCCC diagnosis.

24 Jan 2025·Nucleic Acids Research

The short conserved region-2 of LARP4 interacts with ribosome-associated RACK1 and promotes translation

Article

Author: Gallardo, Isabel Cruz ; Conte, Maria R ; Mattijssen, Sandy ; Pitman, Leah F ; Charlly, Nithin ; Maraia, Richard J ; Coleman, Jennifer C ; Ranjan, Amitabh

AbstractLARP4 interacts with poly(A)-binding protein (PABP) to protect messenger RNAs (mRNAs) from deadenylation and decay, and recent data indicate it can direct the translation of functionally related mRNA subsets. LARP4 was known to bind RACK1, a ribosome-associated protein, although the specific regions involved and relevance had been undetermined. Here, through a combination of in-cell and in vitro methodologies, we identified positions 615–625 in conserved region-2 (CR2) of LARP4 (and 646–656 in LARP4B) as directly binding RACK1. Consistent with these results, AlphaFold2-Multimer predicted high-confidence interaction of CR2 with RACK1 propellers 5 and 6. CR2 mutations strongly decreased LARP4 association with cellular RACK1 and ribosomes by multiple assays, whereas PABP association was less affected, consistent with independent interactions. The CR2 mutations decreased LARP4’s ability to stabilize a β-globin mRNA reporter containing an AU-rich element (ARE) to higher degree than β-globin and GFP (green fluorescent protein) mRNAs lacking the ARE. We show LARP4 robustly increases translation of β-glo-ARE mRNA, whereas the LARP4 CR2 mutant is impaired. Analysis of nanoLuc-ARE mRNA for production of luciferase activity confirmed LARP4 promotes translation efficiency, while CR2 mutations are disabling. Thus, LARP4 CR2-mediated interaction with RACK1 can promote translational efficiency of some mRNAs.

01 Nov 2024·Veterinary Microbiology

Cellular RNA-binding proteins LARP4 and PABPC1 synergistically facilitate viral translation of coronavirus PEDV

Article

Author: Sun, Xin-Yue ; Wang, Xiao-Jia ; Tian, Wen-Jun ; Wang, Jing ; Zhang, Xiu-Zhong

Coronaviruses are causing epizootic diseases and thus are a substantial threat for both domestic and wild animals. These viruses depend on the host translation machinery to complete their life cycle. The current paper identified cellular RNA-binding proteins (RBPs), La-related protein 4 (LARP4) and polyadenylate-binding protein cytoplasmic 1 (PABPC1), as critical regulators of efficient translation of the coronavirus porcine epidemic diarrhea virus (PEDV) mRNA. In Vero cells, PEDV infection caused LARP4 to migrate from the nucleus to the cytoplasm in a chromosome region maintenance1 (CRM1)-independent pathway. In the absence of the nuclear export signal of LARP4, viral translation was not promoted by LARP4. A further study unveiled that the cytoplasmic LARP4 binds to the 3'-terminal untranslated region (3'UTR) of PEDV mRNA with the assistance of PABPC1 to facilitate viral translation. LARP4 knockdown reduced the promotion of the PABPC1-induced 3'UTR translation activity. Moreover, the rabbit reticulocyte lysate (RRL) system revealed that the prokaryotic expressed protein LARP4 and PABPC1 enhance PEDV mRNA translation. To our knowledge, this is the first study demonstrating that PEDV induces nucleo-cytoplasmic shuttling of LARP4 to enhance its own replication, which broadens our insights into how viruses use host's RBPs for the efficient translation of viral mRNA.

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LARP4

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