Profile-based data base scanning for animal L-type lectins and characterization of VIPL, a novel VIP36-like endoplasmic reticulum protein.
Consensus profiles were established to screen data bases for novel animal L-type lectins. The profiles were generated from linear sequence motifs of the human L-type lectin-like membrane proteins ERGIC-53, ERGL, and VIP36 and by optimal alignment of the entire carbohydrate recognition domain of these proteins. The search revealed numerous orthologous and homologous L-type lectin-like proteins in animals, protozoans, and yeast, as well as the sequence of a novel family member related to VIP36, named VIPL for VIP36-like. Sequence analysis suggests that VIPL is a ubiquitously expressed protein and appeared earlier in evolution than VIP36. The cDNA of VIPL was cloned and expressed in cell culture. VIPL is a high-mannose type I membrane glycoprotein with similar domain organization as VIP36. Unlike VIP36 and ERGIC-53 that are predominantly associated with postendoplasmic reticulum (ER) membranes and cycle in the early secretory pathway, VIPL is a non-cycling resident protein of the ER. Mutagenesis experiments indicate that ER retention of VIPL involves a RKR di-arginine signal. Overexpression of VIPL redistributed ERGIC-53 to the ER without affecting the cycling of the KDEL-receptor and the overall morphology of the early secretory pathway. The results suggest that VIPL may function as a regulator of ERGIC-53.
Nufer
Oliver
O
Biozentrum, University of Basel, Klingelbergstrasse 70, CH-4056 Basel, Switzerland.
Mitrovic
Sandra
S
Hauri
Hans-Peter
HP
D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D000818:Animals; D019556:COS Cells; D002352:Carrier Proteins / Q000032:analysis* / Q000737:chemistry / Q000502:physiology; D004721:Endoplasmic Reticulum / Q000737:chemistry; D006801:Humans; D037102:Lectins / Q000032:analysis* / Q000737:chemistry / Q000502:physiology; D037241:Mannose-Binding Lectins / Q000032:analysis; D008565:Membrane Proteins / Q000032:analysis* / Q000737:chemistry / Q000502:physiology; D026901:Membrane Transport Proteins; D008969:Molecular Sequence Data; D019892:eIF-2 Kinase / Q000502:physiology
D002352:Carrier Proteins; C084004:LMAN1 protein, human; C086797:LMAN2 protein, human; D037102:Lectins; D037241:Mannose-Binding Lectins; D008565:Membrane Proteins; D026901:Membrane Transport Proteins; D019892:eIF-2 Kinase