EH Domain-Containing 2 Deficiency Restricts Adipose Tissue Expansion and Impairs Lipolysis in Primary Inguinal Adipocytes

Lipid uptake can be facilitated via caveolae, specific plasma membrane invaginations abundantly expressed in adipocytes. The dynamin-related protein EH domain-containing 2 (EHD2) stabilizes caveolae at the cell surface. Here, we have examined the importance of EHD2 for lipid handling using primary adipocytes isolated from EHD2 knockout (Ehd2−/−) C57BL6/N mice. Following high-fat diet (HFD) feeding, we found a clear impairment of epididymal, but not inguinal, adipose tissue expansion in Ehd2−/− compared with Ehd2+/+ (WT) mice. Cell size distribution analysis revealed that Ehd2−/− mice had a lower proportion of small adipocytes, and an accumulation of medium-sized adipocytes in both epididymal and inguinal adipose tissue. Further, PPARγ activity, FABP4 and caveolin-1 expression were decreased in adipocytes isolated from Ehd2−/− mice. Inguinal adipocytes isolated from Ehd2−/− mice displayed reduced lipolysis in response to beta adrenergic receptor agonist, which was associated with reduced phosphorylation of perilipin-1 and hormone sensitive lipase (HSL). This impairment could not be rescued using a cAMP analog, indicating that impaired lipolysis in Ehd2−/− primary adipocytes likely occurs at the level of, or downstream of, protein kinase A (PKA). Altogether, these findings pinpoint the importance of EHD2 for maintained intracellular lipid metabolism, and emphasize differences in mechanisms regulating lipid handling in various adipose-tissue depots.

The Eps15 homology (EH) domain-containing protein 3, EHD3 is differentially expressed in the brains of patients with schizophrenia.

Visual and auditory hallucinations are a cardinal feature of psychotic disorders (1). We mined published and public microarray datasets (2, 3) to discover differentially expressed genes in schizophrenia and schizoaffective disorder. We found significant differential expression of the gene encoding the Eps15 homology (EH) domain-containing protein 3, EHD3 in neurons of the dorsolateral pre-frontal cortex from patients with schizophrenia and schizoaffective disorder.

EH domain binding protein 1-like 1 (EHBP1L1), a protein with calponin homology domain, is expressed in the rat testis

SummaryIn this paper, with the aim to find new genes involved in mammalian spermatogenesis, we isolated, for the first time in the rat testis, a partial cDNA clone that encoded EH domain binding protein 1-like 1 (Ehbp1l1), a protein that has a single calponin homology domain (CH). Bioinformatic analysis showed that EHBP1l1 contains three domains: the N-terminal C2-like, the CH and the C-terminal bivalent Mical/EHBP Rab binding (bMERB) domains, which are evolutionarily conserved in vertebrates. We found that Ehbp1l1 mRNA was expressed in several rat tissues, including the liver, intestine, kidney and also in the testis during its development, with a higher level in testis from 12-month-old animals. Interestingly, in situ hybridization experiments revealed that Ehbp1l1 is specifically expressed by types I and II spermatocytes, this result was validated by RT-PCR performed on total RNA obtained from enriched fractions of different testicular cell types. As EHBP1l1 has been described as linked to vesicular transport to the actin cytoskeleton and as an effector of the small GTPase Rab8, we hypothesized that it could participate both in cytoskeletal remodelling and in the regulation of vesicle sorting from the trans-Golgi network to the apical plasma membrane. Our findings provide a better understand of the molecular mechanisms of the differentiation process of spermatogenesis; Ehbp1l1 may also be used as a new marker of testicular activity.

Distinct EH domains of the endocytic TPLATE complex confer lipid and protein binding

Clathrin-mediated endocytosis (CME) is the gatekeeper of the plasma membrane. In contrast to animals and yeasts, CME in plants depends on the TPLATE complex (TPC), an evolutionary ancient adaptor complex. The mechanistic contribution of the individual TPC subunits to plant CME remains however elusive. In this study, we used a multidisciplinary approach to elucidate the structural and functional roles of the evolutionary conserved N-terminal Eps15 homology (EH) domains of the TPC subunit AtEH1/Pan1. By integrating high-resolution structural information obtained by X-ray crystallography and NMR spectroscopy with all-atom molecular dynamics simulations, we provide structural insight into the function of both EH domains. Whereas one EH domain binds negatively charged PI(4,5)P2 lipids, unbiased peptidome profiling by mass-spectrometry revealed that the other EH domain interacts with the double N-terminal NPF motif of a novel TPC interactor, the integral membrane protein Secretory Carrier Membrane Protein 5 (SCAMP5). Furthermore, we show that AtEH/Pan1 proteins control the internalization of SCAMP5 via this double NPF peptide interaction motif. Collectively, our structural and functional studies reveal distinct but complementary roles of the EH domains of AtEH/Pan1 have in plant CME and connect the internalization of SCAMP5 to the TPLATE complex.

Effect of EH domain containing protein 2 on the biological behavior of clear cell renal cell carcinoma

To investigate the effects of EH domain containing protein 2 (EHD2) on clear cell renal cell carcinoma (ccRCC) and provide new insights for the clinical treatment of rental cancer. Forty patients (26 males and 14 females, 62.4 ± 5.7 years old) with ccRCC were selected from January 2015 to December 2016 to serve as research subjects in this study. The EHD2 protein expression in the tumor tissues and adjacent healthy tissues of ccRCC patients were detected by Western Blot assay. The cells of ccRCC cell lines RLC-310 and 786-O were divided into normal control group (control), no-load control group (pLV), EHD2 overexpression group (pLV-EHD2), and EHD2 interference group (pLV-siEHD2). The expression levels of EHD2 protein in each group of cells were detected by western blot. The cell proliferation was detected by Cell Counting Kit-8 (CCK-8) assay. Wound healing assay was performed to check the cell migration ability. Transwell invasion assay was used to detect the cell invasion ability. Cell apoptosis was detected by flow cytometry. The expression level of EHD2 was significantly increased in pLV-EHD2 group and decreased in pLV-siEHD2 group compared with control group and pLV-siEHD2 group, indicating the successfully established EHD2 overexpression cell line and EHD2 RNA interference cell line. EHD2 overexpression enhanced the proliferation, invasion, and migration but inhibited the apoptosis of ccRCC cells, while EHD2 interference showed opposite functions. EHD2 interference can inhibit the development of ccRCC by inhibiting the proliferation, invasion, and migration, and EHD2 can potentially serve as a molecular target for the clinical treatment of ccRCC.

EHD2 restrains dynamics of caveolae by an ATP-dependent, membrane-bound, open conformation

The EH-domain–containing protein 2 (EHD2) is a dynamin-related ATPase that confines caveolae to the cell surface by restricting the scission and subsequent endocytosis of these membrane pits. For this, EHD2 is thought to first bind to the membrane, then to oligomerize, and finally to detach, in a stringently regulated mechanistic cycle. It is still unclear how ATP is used in this process and whether membrane binding is coupled to conformational changes in the protein. Here, we show that the regulatory N-terminal residues and the EH domain keep the EHD2 dimer in an autoinhibited conformation in solution. By significantly advancing the use of infrared reflection–absorption spectroscopy, we demonstrate that EHD2 adopts an open conformation by tilting the helical domains upon membrane binding. We show that ATP binding enables partial insertion of EHD2 into the membrane, where G-domain–mediated oligomerization occurs. ATP hydrolysis is related to detachment of EHD2 from the membrane. Finally, we demonstrate that the regulation of EHD2 oligomerization in a membrane-bound state is crucial to restrict caveolae dynamics in cells.