Haprin, a Novel Haploid Germ Cell-specific RING Finger Protein Involved in the Acrosome Reaction

Kitamura, Koichi; Tanaka, Hiromitsu; Nishimune, Yoshitake

doi:10.1074/jbc.m304306200

Cited by 53 publications

(62 citation statements)

References 42 publications

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“…Trim proteins are defined by a conserved domain architecture, consisting of an N-terminal RING finger domain, in combination with adjacent B-box-type zinc fingers and a coiled-coil motif. Mammalian Trim36 localizes to microtubules in cultured cells and is thought to have a role in acrosome exocytosis (Kitamura et al, 2003;Kitamura et al, 2005). Here we show that, in Xenopus, trim36 mRNA is localized vegetally in the oocyte and is enriched in the germ plasm and adult germ cells.…”

Section: Introductionmentioning

confidence: 66%

Vegetally localized Xenopus trim36 regulates cortical rotation and dorsal axis formation

Cuykendall

Houston

2009

Development

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Specification of the dorsoventral axis in Xenopus depends on rearrangements of the egg vegetal cortex following fertilization, concomitant with activation of Wnt/β-catenin signaling. How these processes are tied together is not clear, but RNAs localized to the vegetal cortex during oogenesis are known to be essential. Despite their importance, few vegetally localized RNAs have been examined in detail. In this study, we describe the identification of a novel localized mRNA, trim36, and characterize its function through maternal loss-of-function experiments. We find that trim36 is expressed in the germ plasm and encodes a ubiquitin ligase of the Tripartite motif-containing (Trim) family. Depletion of maternal trim36 using antisense oligonucleotides results in ventralized embryos and reduced organizer gene expression. We show that injection of wnt11 mRNA rescues this effect, suggesting that Trim36 functions upstream of Wnt/β-catenin activation. We further find that vegetal microtubule polymerization and cortical rotation are disrupted in trim36-depleted embryos, in a manner dependent on Trim36 ubiquitin ligase activity. Additionally, these embryos can be rescued by tipping the eggs 90° relative to the animal-vegetal axis. Taken together, our results suggest a role for Trim36 in controlling the stability of proteins regulating microtubule polymerization during cortical rotation, and subsequently axis formation.

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Section: Introductionmentioning

confidence: 66%

Vegetally localized Xenopus trim36 regulates cortical rotation and dorsal axis formation

Cuykendall

Houston

2009

Development

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“…The third, TRIM36, had previously been reported by Reymond et al (2), but was represented as only possessing an N-terminal RBCC/TRIM domain. Validating our findings, two other groups identified and reported TRIM36 during the course of this study and also determined that it possesses a MID1/MID2-like domain architecture that includes both C-terminal FN3 and B30.2-like domains (14,31).…”

Section: Discussionmentioning

confidence: 99%

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confidence: 99%

“…Support for this notion came recently from the report of Haprin, a new testis-specific FN3 motif-and B30.2-like domain-containing RBCC protein that is clearly the murine ortholog of a sequence identified in our screen. Functional data suggest that Haprin plays a regulatory role in exocytosis of the sperm vesicle (14).In this study, we report the identification of two novel proteins, TRIFIC and TNL, which share the same overall domain organization as MID1, MID2, TRIM9 (the human ortholog of rat Spring), and TRIM36 (the human ortholog of mouse Haprin), and show for the first time that all analyzed members of this RBCC subfamily associate with the microtubule * This work was supported in part by Project Grant 157958 from the National Health and Medical Research Council of Australia. The costs of publication of this article were defrayed in part by the payment of page charges.…”

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confidence: 99%

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Subclassification of the RBCC/TRIM Superfamily Reveals a Novel Motif Necessary for Microtubule Binding

Short¹,

Cox²

2006

Journal of Biological Chemistry

287

358

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The biological significance of RBCC (N-terminal RING finger/Bbox/coiled coil) proteins is increasingly being appreciated following demonstrated roles in disease pathogenesis, tumorigenesis, and retroviral protective activity. Found in all multicellular eukaryotes, RBCC proteins are involved in a vast array of intracellular functions; but as a general rule, they appear to function as part of large protein complexes and possess ubiquitin-protein isopeptide ligase activity. Those members characterized to date have diverse C-terminal domain compositions and equally diverse subcellular localizations and functions. Using a bioinformatics approach, we have identified some new RBCC proteins that help define a subfamily that shares an identical domain arrangement (MID1, MID2, TRIM9, TNL, TRIM36, and TRIFIC). Significantly, we show that all analyzed members of this subfamily associate with the microtubule cytoskeleton, suggesting that subcellular compartmentalization is determined by the unique domain architecture, which may in turn reflect basic functional similarities. We also report a new motif called the COS box, which is found within these proteins, the MURF family, and a distantly related non-RBCC microtubule-binding protein. Notably, we demonstrate that mutations in the COS box abolish microtubule binding ability, whereas its incorporation into a nonmicrotubule-binding RBCC protein redirects it to microtubule structures. Further bioinformatics investigation permitted subclassification of the entire human RBCC complement into nine subfamilies based on their varied C-terminal domain compositions. This classification schema may aid the understanding of the molecular function of members of each subgroup and their potential involvement in both basic cellular processes and human disease.Members of the RBCC (N-terminal RING finger/B-box/coiled coil) or TRIM (tripartite motif) family of proteins perform a diverse array of cellular roles, yet are believed to share some functional properties: 1) act as a scaffold for the assembly of larger multiprotein complexes and 2) possess RING-dependent ubiquitin ligase activity (1, 2). The RBCC domain can be found in isolation or in combination with a variety of other C-terminal domains, including the NHL (NCL-1/HT2A/LIN-41 repeat), immunoglobulin, MATH (meprin and tumor necrosis factor receptor-associated factor homology), B30.2-like/RFP (Ret finger protein)/SPRY (SplA and ryanodine receptor) (the largest subgroup in humans), ARF (ADP-ribosylation factor), PHD (plant homeodomain finger), and BROMO domains (1, 2). As a family of proteins, their biological significance is perhaps best highlighted by the growing number that have a demonstrated role in disease pathogenesis, including immunological and developmental disorders, tumorigenesis, and retroviral protective activity (3-7).We have previously identified and characterized two RBCC proteins, MID1 and its closely related homolog, MID2. MID1 and MID2 contain a B30.2-like domain at their C terminus and a single fibronectin type III (FN3...

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“…A haploid germ cell-specific gene haprin encodes a RBCC motif protein, called haprin . It localizes to the acrosome of spermatids and spermatozoa and plays a role in the acrosome reaction by mediating protein complex formation via the RBCC motif (Kitamura et al, 2003(Kitamura et al, , 2005a. The RING finger protein (RNF151) [ID: T2-270] is expressed in elongating spermatids.…”

Section: Microscopy Research and Techniquementioning

confidence: 99%

Surfing the wave, cycle, life history, and genes/proteins expressed by testicular germ cells. Part 2: Changes in spermatid organelles associated with development of spermatozoa

Hermo

Pelletier

Cyr

et al. 2009

Microscopy Res & Technique

100

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Spermiogenesis is a long process whereby haploid spermatids derived from the meiotic divisions of spermatocytes undergo metamorphosis into spermatozoa. It is subdivided into distinct steps with 19 being identified in rats, 16 in mouse and 8 in humans. Spermiogenesis extends over 22.7 days in rats and 21.6 days in humans. In this part, we review several key events that take place during the development of spermatids from a structural and functional point of view. During early spermiogenesis, the Golgi apparatus forms the acrosome, a lysosome-like membrane bound organelle involved in fertilization. The endoplasmic reticulum undergoes several topographical and structural modifications including the formation of the radial body and annulate lamellae. The chromatoid body is fully developed and undergoes structural and functional modifications at this time. It is suspected to be involved in RNA storing and processing. The shape of the spermatid head undergoes extensive structural changes that are species-specific, and the nuclear chromatin becomes compacted to accommodate the stream-lined appearance of the sperm head. Microtubules become organized to form a curtain or manchette that associates with spermatids at specific steps of their development. It is involved in maintenance of the sperm head shape and trafficking of proteins in the spermatid cytoplasm. During spermiogenesis, many genes/proteins have been implicated in the diverse dynamic events occurring at this time of development of germ cells and the absence of some of these have been shown to result in subfertility or infertility.

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Haprin, a Novel Haploid Germ Cell-specific RING Finger Protein Involved in the Acrosome Reaction

Cited by 53 publications

References 42 publications

Vegetally localized Xenopus trim36 regulates cortical rotation and dorsal axis formation

Vegetally localized Xenopus trim36 regulates cortical rotation and dorsal axis formation

Subclassification of the RBCC/TRIM Superfamily Reveals a Novel Motif Necessary for Microtubule Binding

Surfing the wave, cycle, life history, and genes/proteins expressed by testicular germ cells. Part 2: Changes in spermatid organelles associated with development of spermatozoa

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