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8.A.28.1.5
Junctate, Junctin, Aspartate beta-hydroxylase, ASPH, BAH of 758 aas and 1 N-terminal TMS. It has enzyme activity, but is also a Ca2+-sensing ER protein, a structural component of ER-PM junctions where Orai1 and STIM1 cluster and interact in T cells (Srikanth et al. 2012). It plays a role in cardiac Ca2+ handeling (homeostatis), contractility and heart failure (Gergs et al. 2007).  Two other proteins of the complex are: Triadin and Calsequestrin. Junctin is a transmembrane protein of striated muscles, located at the junctional sarcoplasmic reticulum (SR). It is characterized by a luminal C-terminal tail, through which it functionally interacts with calsequestrin and the ryanodine receptor (RyR). In non-muscle cells, junctin and calsequestrin assemble in long linear regions within the endoplasmic reticulum, mirroring the formation of calsequestrin polymers (Rossi et al. 2022). In differentiating myotubes, the two proteins colocalize at triads, where they assemble with other proteins of the junctional SR. Two KEKE motifs can bind calsequestrin, and stretches of charged amino acids downstream of these motifs can also bind calsequestrin and the RyR. Deletion of even one of these regions impaired the ability of junctin to localize at the junctional SR, suggesting that interaction with other proteins at this site represents a key element in junctin targeting (Rossi et al. 2022).

Accession Number:Q12797
Protein Name:Aspartyl/asparaginyl beta-hydroxylase
Length:758
Molecular Weight:85863.00
Species:Homo sapiens (Human) [9606]
Number of TMSs:2
Location1 / Topology2 / Orientation3: Endoplasmic reticulum membrane1 / Single-pass type II membrane protein2
Substrate

Cross database links:

Structure:
5APA   5JQY   5JTC   5JZ6   5JZ8   5JZA   5JZU   6Q9F   6Q9I   6QA5   [...more]

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Predict TMSs (Predict number of transmembrane segments)
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FASTA formatted sequence
1:	MAQRKNAKSS GNSSSSGSGS GSTSAGSSSP GARRETKHGG HKNGRKGGLS GTSFFTWFMV 
61:	IALLGVWTSV AVVWFDLVDY EEVLGKLGIY DADGDGDFDV DDAKVLLGLK ERSTSEPAVP 
121:	PEEAEPHTEP EEQVPVEAEP QNIEDEAKEQ IQSLLHEMVH AEHVEGEDLQ QEDGPTGEPQ 
181:	QEDDEFLMAT DVDDRFETLE PEVSHEETEH SYHVEETVSQ DCNQDMEEMM SEQENPDSSE 
241:	PVVEDERLHH DTDDVTYQVY EEQAVYEPLE NEGIEITEVT APPEDNPVED SQVIVEEVSI 
301:	FPVEEQQEVP PETNRKTDDP EQKAKVKKKK PKLLNKFDKT IKAELDAAEK LRKRGKIEEA 
361:	VNAFKELVRK YPQSPRARYG KAQCEDDLAE KRRSNEVLRG AIETYQEVAS LPDVPADLLK 
421:	LSLKRRSDRQ QFLGHMRGSL LTLQRLVQLF PNDTSLKNDL GVGYLLIGDN DNAKKVYEEV 
481:	LSVTPNDGFA KVHYGFILKA QNKIAESIPY LKEGIESGDP GTDDGRFYFH LGDAMQRVGN 
541:	KEAYKWYELG HKRGHFASVW QRSLYNVNGL KAQPWWTPKE TGYTELVKSL ERNWKLIRDE 
601:	GLAVMDKAKG LFLPEDENLR EKGDWSQFTL WQQGRRNENA CKGAPKTCTL LEKFPETTGC 
661:	RRGQIKYSIM HPGTHVWPHT GPTNCRLRMH LGLVIPKEGC KIRCANETKT WEEGKVLIFD 
721:	DSFEHEVWQD ASSFRLIFIV DVWHPELTPQ QRRSLPAI